Mikado's physical appearance is one that does not stand out from a crowd. He has short black hair, grayish-blue eyes, a rather soft expression, and a small demeanor. Aside from his Raira Academy uniform, his casual attire usually consists of a green and white jacket and jeans.
Initially, Mikado is portrayed as a polite, soft-spoken boy, who at times can be quite childish and naive. This is likely a result of his small town upbringing; as he moves to Ikebukuro he was amazed and overwhelmed by the sheer size and energy of the city, and thus he felt small and insignificant. He was bored of the average life he had previously led, and moved to Tokyo in search of adventure and revels in all the supernatural events that transpire around him despite the obvious danger. This desire for the unknown also causes Mikado to show utter disgust toward people he finds either boring (like Hiroshi) or hypocritical (like Namie).
Despite his timid personality, he is shown to have a fairly strong will, and he does have moments where he openly expresses his opinion such as when he tells Anri she should be proud of trying to surpass Mika Harima. Mikado also has a strong moral center and actively speaks out against those who commit crimes or hurt others, even if it, more often than not, proves fruitless.
Mikado also has a much darker side to his personality which is hinted at more strongly in the manga and light novels. Because of his strong desire to evolve, Mikado detests how "normal" he looks in comparison to his friends who all seem to have some kind of special ability or profession. This frustration reaches its peak during the events of the Akane and Blue Squares Arcs, which causes Mikado to develop a much more cold-hearted demeanor. He believes that in order to protect his friends and continue to grow, he must seize power by force using any means necessary.
While in this mindset, Mikado is much more ruthless and manipulative than he appears to be and is very capable at using intimidation to reach his goals. While it may initially seem like Mikado has split personalities, it is theorized by Aoba and Izaya that the colder version of Mikado is his real personality while his timid side is the fake one.
Mikado grew up in the small town of Saitama and led a very uneventful life. Most of Mikado's time was spent online chatting with others and listening to exciting stories from the big city that he would hear from his childhood friend, Masaomi Kida. At some point during this time, Mikado and a few online friends decided to create a fake online group called the Dollars as an elaborate prank to play on others. They passed out passwords to the site and made all kinds of outrageous claims about the gang's activities. Initially, the joke went as planned and people started joining the group despite it being a little more than a forum. However, the group continued to grow exponentially, even after they stopped giving the password. Furthermore, many people were using the Dollars as a scapegoat to commit crimes. Almost all the founders left the group as they feared it could be traced back to them while Mikado stayed to see what the outcome would be.
Mikado initially tried to convince others on the forums to put a stop to the criminal activities but was mocked as a result. However, his ideas resonated with others and soon, many Dollars members were actively correcting the mistakes made by other members and even participated in community service activities. Because of this, Mikado continued to act as an admin of sorts for the site, occasionally making announcement but rarely giving orders as he believed the Dollars to be a group without restrictions as the original proposal said.
At the behest of Masaomi, Mikado eventually decided to move to Ikebukuro and attend Raira Academy as a way to break the monotony of his life in the country. He also wished to see what the Dollars behaved like in the city as most of its members were in Ikebukuro.
Dollars/Mika Harima ArcMikado reunites with Masaomi at the train station and the two of them get quickly reacquainted. Masaomi briefly introduces Mikado to several of the more interesting locals in Ikebukuro including Kadota's Gang and Simon from Russia Sushi. Mikado is also warned to stay away from Izaya Orihara and Shizuo Heiwajima. Toward the end of the night, the two of them catch a glimpse of the Black Rider as she rides by.
Mikado is a member of a chatroom under the handle "TarouTanaka" and often chats with two other users, "Setton" and "Kanra." Throughout the arc, the three of them discuss various topics that occur around the city including the Dollars, the Black Rider, and a recent string of kidnappings.
The next day, Mikado attends Raira Academy and introduces himself in class, briefly meeting Seiji Yagiri, who leaves just as quickly as he arrives. He soon develops an interest in Anri Sonohara, who he notices is staring at him, and even volunteers to be a class representative alongside her. He attempts to speak with her but Anri remains distant.
After school he walks with Masaomi around town, continuing to ask him about various topics around Ikebukuro. Most of his questions seem to focus on the Dollars but before they can continue, they discover Anri being bullied. As Mikado tries to think of a way to help her, Izaya Orihara suddenly appears and pushes Mikado in between Anri and the bullies. Izaya soon chases the bullies off by crushing one of their phones and properly introduces himself to the three students. Mikado notices that Masaomi is visibly uncomfortable with Izaya around but before he can inquire, their conversation is interrupted by the arrival of Shizuo Heiwajima.
Shizuo attacks Izaya relentlessly, almost getting Mikado caught in the crossfire if not for the timely intervention of Simon. As the situation gets more chaotic, Mikado suddenly grabs Anri's arm and makes a break for it, leaving Masaomi behind. Eventually, he lets go of Anri and the two awkwardly part ways.
Mikado, Anri, and Masaomi soon start regularly hanging out with each other and attempt to get to know each other better. Anri begins talking about Mika Harima, her friend who went missing just before school started. She also shows him a photo of when they were in middle school.
As the trio parts ways, Mikado hears the black rider and attempts to get another glimpse of it. However, he immediately runs into a girl with a scar around her neck, pleading for help. As the Black Rider rounds the corner, he realizes she's being chased by it and immediately takes her with him, losing the Black Rider in the subway. Mikado tells the girl to stay in his apartment while he tries to figure out what to do. Mikado also notes how the scar looks as though someone had sewn the girl's head onto her body somehow.
He tells Masaomi about the incident the next day, but Masaomi is more than a little skeptical. The next day, as Mikado continues to worry, Masaomi decides to take him to see Ryo Takiguchi, who is rumored to be a part of the Dollars. Ryo confirms his membership without hesitation and gives a bit of insight into the group as a whole, describing it as a colorless gang.
Later in the day, as Mikado and Anri are about to leave, they are stopped by one of Anri's bullies with her boyfriend. They try to pick a fight with Mikado and Anri but are stopped by the intervention of Izaya and the Black Rider.
Mikado senses danger and parts ways with Anri, leading Izaya and the Black Rider towards a more secluded area. Mikado soon confronts them over why they are following him and about the Rider's connection to the girl with the scar.
The Black Rider properly introduces herself as Celty Sturluson and, after some light prodding, tells Mikado the truth about her nature as a Dullahan, her search for her missing head, and the possibility that the girl might have it.
Mikado agrees to let Celty meet the girl but goes inside first to explain the situation so she doesn't panic. Mikado quickly notices the empty apartment and realizes the girl has left. As this fact dawns on him he gets pinned down by several thugs from Yagiri Pharmaceuticals who interrogate him about the girl's location. The thugs are soon chased out by Celty and Izaya who proceed to help Mikado recover from the attack. As Izaya explains who the thugs were employed to, Mikado's demeanor changes as he realizes that Yagiri Pharmaceuticals has been behind the recent kidnappings as well as the disappearance of Mika Harima. He also realizes that, based on the thugs reaction to Celty, that they may have something to do with Celty's missing head and that it was most likely sewn to Mika's body. Mikado reveals his status as the Dollars founder to Izaya and Celty and asks them for his help.
He learns from the Dollars message board that Kyouhei has found the girl with the scar and is taking care of her. Mikado has Kyouhei meet with Celty while he deals with Yagiri Pharmaceuticals. He sends a message directly to Namie Yagiri, asking to meet her in person. At the same time, he sends out a notice for the first Dollars meeting to be held in the exact same location.
Mikado confronts Namie about her actions and demands that she turn herself in, deliberately trying to keep her attention on him alone. When Namie signals her men to capture him, he surreptitiously sends a mass text to all Dollars members in the vicinity—and a chorus of ringtones goes off in surround sound. With Namie and her men confused and overwhelmed, he is able to slip into the crowd and flee the scene.
Celty rides her motorcycle down a building and into the throng, where she fights off Namie's subordinates. She and Mikado hide from the police in the shadows of an alleyway in the aftermath of the 60-Kai Street gathering, where Seiji stabs Celty in the back; then, with Mikado, Izaya, and members of the van gang looking on, he pulls Mika out of the van. When he asks her to come with him she agrees, much to Mikado's shock.
Seiji acknowledges that he owes Mikado and Namie a great deal, and that he "might" have killed someone when Mikado poses the question. Celty forcefully attempts to prevent him from leaving the scene, but Mika steps between Seiji and Celty's scythe and cries for her to stop. As she weeps, Mikado and Seiji realize that she must be Mika Harima rather than the "dullahan's head." The idea that Seiji did not notice the head was fake sends him to his knees, and Mikado remarks that Seiji and Mika are very similar before taking his leave.
At Raira Academy the next day, Masaomi tells Mikado that the Internet is buzzing over news of a Dollars meet-up yesterday and the appearance of the Black Rider. Seiji and Mika both rejoin Mikado's class, though Mikado finds the latter's attendance the more surprising of the two. With school seemingly back to 'normal', Mikado resolves to take Izaya's advice and evolve as a person.
Mikado plays a minor role during this arc, expressing concerns over the recent slasher attacks as well as confusion regarding a mysterious user named "Saika" who keeps trolling the chat room.
After Anri puts a stop to the slasher attacks and ends up in the hospital, Mikado and Masaomi quickly go to visit her and are relieved at finding her safe. As Mikado makes another attempt at flirting, he is caught off guard when Anri expresses a slight attraction towards Celty, but refrains from mentioning it for fear of drawing Anri into more danger.
Yellow Scarves Arc
After Anri is released from the hospital, Mikado begins to notice that Masaomi has been acting strangely since the Saika incident, as though he was preoccupied with something. Additionally, Mikado also starts seeing more people wearing yellow around the city. He eventually learns that these people are most likely members of the Yellow Scarves, an old color gang that went into hiding a few months before the Dollars gained prominence. The Yellow Scarves begin attacking Dollars members in an attempt to reestablish dominance in Ikebukuro, causing many to fear for their safety. Because of this, Mikado and Masaomi warn Ryo Takiguchi to lay low regarding his status as a Dollars member. Unfortunately, their warning comes too late, as Mikado soon finds out that Ryo was attacked a few days later and goes to visit him in the hospital. Feeling somewhat responsible, Mikado apologizes to Ryo who questions why he feels the need to do so. Ryo eventually asks if Mikado was in the Dollars which Mikado frantically denies. After leaving the hospital, Mikado runs into Kyouhei and talks about recent events. Kyouhei mentions how frustrated some of the Dollars members are at the leader's absence during this incident which adds further fuel to Mikado's stress regarding the issue.
The next day he runs into Seiji and Mika. Mika asks him about how's Anri was doing, saying she seemed distressed about something. Mikado states that he never noticed anything strange which seems to satisfy Mika's curiosity. As they are leaving, Seiji turns to Mikado and gives him some advice regarding Anri. He states that, if he truly loved Anri, then he should accept her for all that she was, regardless of her past.
When he goes home, he reads the Dollars log and finds out that Anri is being chased by the Yellow Scarves. Mikado asks everyone to help her through the message board which prompts many Dollars members to collaborate to help Anri escape. While the rescue was successful, Mikado decides that in order to end the Yellow Scarves attacks, he must take the Dollars out of the equation completely and disbands the Dollars, shutting down BBS.
As Mikado ponders his decision, Celty suddenly pays him a visit. At first Mikado believes it's about his decision to disband the Dollars but Celty tells him she's there to tell the truth about his friends. She tells him about Anri being the wielder of Saika, and that Masaomi is the leader of the Yellow Scarves. Mikado, in shock, asks Celty to take him to see his friends. Celty agrees to take him to see Anri first since she was staying at her house for the night, but learned that she had run away after learning that Masaomi had apparently ordered Shizuo to be shot.
Celty and Mikado head to the Yellow Scarves' hideout but are stopped briefly by Simon who urges Celty to save Masaomi. Celty asks Mikado if he was truly ready to face the truth and Mikado accepts. They drive to the Yellow Scarves hideout to see Anri with Saika, a bloody Masaomi, and the Yellow Scarves teaming up with Horada. Mikado and Anri rush to Masaomi's side and the three start to reconcile.
When Horada orders his men to finish off Mikado and the others, surprisingly, the Yellow Scarves battle each other. Kyouhei reveals that he got a bunch of Dollars members together to put an end to Horada's schemes and infiltrated the meeting. As the battle rages around them, Masaomi punches Horada one last time before falling unconscious. Kyouhei assists Mikado and Anri with taking Masaomi to the hospital.
Mikado meets with Anri the next day and finds out that Masaomi had left Ikebukuro after the Yellow Scarves incident. While Mikado is sad that he left, he and Anri resolve to give Masaomi a proper welcome when he decides to come home. As things quiet down, a new user, Bacura, joins the chatroom, with Mikado quickly realizing he is Masaomi. As the arc closes, Mikado decides to restore the Dollars and reopens the website.
Mikado is watching the news just in time to see Celty being chased by Kinnosuke Kuzuhara on screen. He is slightly worried but knows that Celty should be able to handle it. He logs on to the chatroom and Kanra posts a link to a website. When Mikado clicks on it, he sees a wanted poster for Celty with a 10 million yen reward for her capture, the ones who put up the reward being Yodogiri Shining Corporation, a talent agency. Mikado briefly wonders if he should mobilize the Dollars to help, but decides that they probably wouldn't be able to do much in this situation and may actually even draw more attention to Celty than the wanted poster already has.
The next day, after the opening ceremony for the new year, Mikado and Anri are approached by a first year student named Aoba Kuronuma. The two of them are quickly overwhelmed by Aoba's hyperactive personality and they are persuaded (pressured) into giving Aoba a tour of Ikebukuro since he is new to the area. Mikado and Anri meet up with Erika Karisawa and Walker Yumasaki later that day for advice on showing someone around, since neither Mikado or Anri are very talkative and want to know the best places to show Aoba. Erika and Walker agree and even offer to accompany them while they show Aoba around.
The next day, shortly after Mikado meets with Anri and Aoba, Mikado is suddenly threatened by a small group of former Yellow Scarves members out for revenge. Before things get too serious, however, Kyouhei and the gang rides in and pulls Mikado, Anri, and Aoba into the van. Mikado notices Mairu Orihara and Kururi Orihara also in the van but does not have time to question it as Saburo Togusa begins speeding away on the road. Mikado looks out the window and sees several members of a biker gang called Toramaru riding after them. Kyouhei apologizes for dragging them into the chaotic situation. Several hours into the chase, Celty pulls along side the van along with even more Toramaru members chasing her, explaining that they are after the 10 million yen reward.
After receiving some unexpected assistance from Kinnosuke Kuzuhara, the group continue to get chased by Toramaru until they come to an overpass. Celty tells the others to run away while she holds the gang at bay. Kyouhei's gang drops the high schoolers off several blocks away before the four drive back to help Celty. Mikado and the others run back despite being told to go to the police, as Mikado feels it is his duty to stay with members of the Dollars when they are in trouble, but under the overpass they find Egor and Ruri Hijiribe beating up the Toramaru members while Celty and Kyouhei's gang watch in awe.
A few days later, after things have quieted down and the bounty on Celty's head has been recalled, Mikado and the others take part in the hotpot party at Celty and Shinra's apartment.
In the chatroom, Mikado is pulled into private chat with Masaomi, who tells Mikado not to go out during golden week as well as to make sure no one finds out his connection to the Dollars or that he's even a member at all. Masaomi goes on to say that Dollars is in danger but isn't sure what the reason is. Mikado is confused but agrees to lay low, trusting his friend's judgement (in truth, this was Izaya trying to manipulate Mikado by posing as Masaomi).
The next day, after a student council meeting, Mikado and Anri are approached by Aoba who wanted to go on another tour of Ikebukuro since their last one was interrupted by Toramaru. Mikado, remembering Kida's warning, tries to turn Aoba down so that he could look up info on what was endangering the Dollars. Mikado states that he can't go with Aoba, saying he had some urgent business. Upon hearing this, Aoba began to (not so) subtly flirt with Anri about accompanying him. Anri is oblivious to Aoba's advances but Mikado panics and says that he will show him around but can't go at night, saying it gets too crowded during golden week. Aoba and Anri agree to meet the next day.
Later, at his apartment Mikado starts asking on the chatroom about anything that might have happened to the Dollars. Kururi and Mairu point him to another website which contains a news report. Mikado learns that several members of Toramaru were attacked in Saitama and beaten severely to the point where many of the were sent to the hospital. Along with several burned and destroyed motorbikes, Mikado notices the word DOLLARS spray-painted over Toramaru's logo on a wall in the background of a picture.
Mikado, as the founder, feels responsible for the incident and wonders what he should do. Mikado then gets a call from Izaya. Having no one else to turn to at the moment, Mikado talks to Izaya for advice on the matter. Izaya mentions the captain of Toramaru, Chikage Rokujou, is in town looking for revenge and suggests that Mikado simply quits the Dollars but Mikado denies that option almost immediately. Izaya takes this as a sign that Mikado is more attached to Dollars than he initially expected and deduces that Mikado is worried that the Dollars are getting out of control. Izaya also states that even though Mikado wants to solve the issue, he is actually excited about the whole situation. Mikado doesn't entirely deny this, and Izaya ends the conversation by offering his help should Mikado need it, hinting at ulterior motives in the process.
Mikado tries to think of a plan to resolve the incident, but keeps drawing a blank. The feeling of excitement begins to swell up in Mikado at the recent turn of events but he pushes it out of his mind. Someone then knocks on Mikado's door and it is soon revealed to be Aoba. Before Mikado can ask what is happening, he notices several thuggish looking individuals wearing blue standing behind Aoba. Wearing the same cheerful yet eerie smile, Aoba tells Mikado to come with him.
Mikado, Aoba, and the rest of the delinquents arrived at an abandoned factory warehouse. Aoba asks Mikado if he was looking into the incident in Saitama. Mikado confirms that he was, but is shocked when Aoba casually admits that "We did it." The thugs who accompanied them began to chuckle when Aoba gave his confession. Aoba states that it was revenge for chasing everyone halfway across the city several months ago. He also goes on to say that although they attacked Toramaru in the name of the Dollars, Aoba and his group also go by the name Blue Squares. As Mikado absorbed this information, his cell phone, along with everyone else, began to ring with a message that Chikage Rokujou was attacking Kyouhei and his gang.
Ignoring the message, Aoba offers the role of leadership over to Mikado. Mikado is perplexed at the offer and suspects an ulterior motive. Aoba explains that he wouldn't be the leader of the Dollars but specifically of the Blue Squares, who would act as a special unit that only answered to him. Mikado tries to turn him down, saying he wouldn't get involved in something like that. Aoba then asks why Mikado is smiling if he didn't want what was offered.
Dollars and Blue Square Arc
Mikado tries to deny Aoba's statement but can't get over a strange sense of joy that emanated from the bottom of his heart. Mikado then realized that Aoba was correct but he didn't know why he smiled in the first place. As several thoughts swirl around in Mikado's head, Aoba draws attention to the countless messages left by other Dollars members. Mikado tries to stall for time but Aoba brings up the meeting with Anri they had set up the day before. Aoba makes subtle threats towards Anri, which causes a sudden surge of "black emotions" to well up in Mikado which he pushes to the back of his mind.
The two are interrupted by Celty's ringtone echoing through the warehouse. Having been spotted, Celty explains that she was watching to make sure nothing bad happened and told the others to continue as though she weren't there. Before Mikado or Aoba can question her further, several Toramaru members also rush in, recognizing Aoba and his gang as the ones who attacked them. Aoba calls Mikado "Captain" which causes the Toramaru members to turn their attention towards him. Celty takes Mikado onto the back of her motorbike while Aoba and the Blue Squares hold off Toramaru.
Celty explains the situation to Mikado as they meet up with Anri and Akane who are surrounded by members of the Awakusu. Before they can speak, even more Toramaru members arrive demanding they hand over "the kid" (Mikado). The Awakusu take it as a threat against Akane and begin to fight the Toramaru members, telling Celty to take Akane to a safe place. Celty transforms her motorbike to a horse and carriage to accommodate the larger passenger count and the four of them ride away to a parking lot halfway across town.
Mikado takes a moment to sort out all that's happened and realizes that Aoba's goal is probably to take control of Dollars and use him as a figure head. As Mikado thinks of a solution, he gets another disturbing text message on his phone. "Nakura" posts a picture of one of Chikage Rokujou's girlfriends, Non, eating with Rio Kamichika and several others. He goes on to suggest that the Dollars kidnap them to try and threaten Toramaru into calling off their attacks on Dollars. Without thinking, Mikado rushes off to the cafe where they were seen with Anri and Vorona chasing after him.
Mikado arrives just as Non, Rio, and their friends are about to be kidnapped. He tells the others to stop as a fellow member of the Dollars but gets insulted and kicked as a result. The men shove the girls into the back of the van and drive off, leaving a few of their friends (including Hiroshi), behind to finish Mikado off. As they beat down on him, Mikado doesn't feel fear but another surge of "black emotions" that he felt earlier as he falls unconscious. When Mikado comes to, he sees Anri dispatching the rogue Dollars members with Saika. Mikado is ashamed at his helplessness as Anri helps him up. Mikado gets another message, saying that the kidnappers are on their way to stop Kyouhei and Chikage at Raira Academy. Mikado and Anri head off while Vorona tails them silently.
At Raira, they can see Kyouhei and Chikage fighting off in the distance and the kidnappers and the girls approaching slowly in their van. As Mikado turns around, he sees Vorona appear out of nowhere and attack Anri. Anri tells Mikado to run but is stunned by Vorona's flash bomb. Mikado is left on the ground while Anri and Vorona run off to continue their fight. Mikado is frustrated at being glossed over like that as he waits for his vision to return.
When it does, he sees Shizuo standing over him with Vorona's motorbike on his shoulder. Shizuo looks Mikado in the eyes and declares that he's resigning from the Dollars, saying that he wasn't going to be part of a group that was low enough to resort to kidnapping high school students. The "black emotions" returned, this time aimed at himself for being so useless at such a crucial time.
After the fighting has ended and the victims were rescued, Mikado sees Non and Chikage limping away on the sidewalk. Mikado runs up to them and apologizes as the leader of the Dollars. Chikage appreciates the gesture, but can't believe that someone as ordinary as Mikado could possibly be the leader. Although it wasn't meant as an insult, for someone like Mikado who strives to live an unordinary life, it was the last push he needed to go over the edge. Mikado crumples down and cries at all that's happened.
The next day, Mikado calls Aoba and the Blue Squares back to the old Warehouse to settle their agreement. He explains that the direction Dollars is heading isn't right. He knows that he can't set rules for the Dollars since that goes against what the Dollars were made for. Mikado decides to opt for the next best thing: power. Mikado says that if Aoba and the Blue Squares offer him their strength, then they can use him however they want. Mikado pulls out a sheet of paper and a ballpoint pen to make the agreement official.
Aoba is perplexed but walks over to sign the paper anyway. Just as Aoba sees that there is nothing on the paper at all, Mikado jabs the pen into Aoba's hand, piercing it all the way through, blood splattering all over the paper. Aoba looks Mikado in the eyes and sees nothing but a cold, contemptuous glare staring back. Mikado states that regardless of what Aoba planned to do to him, he still put Anri in danger by drawing her into the conflict with the Dollars and Toramaru. As his first order, he demands that Aoba "Stomach the full wrath of his anger."
Before the other Blue Squares can react, Aoba tells them to back off. Aoba meekly agrees to Mikado's terms, realizing that Mikado isn't going to back down...or release his grasp, until he did so. As Aoba swears loyalty, Mikado went through a complete change in his personality and reverts back to his usual cheerful self, yanking the pen out of Aoba's hand and proceeding to expertly bandage up the wound he left. Aoba whispers in his heart that both he and Izaya had underestimated Mikado and mentions that he has "Far from shown his true character."
Daily Life Arc
Mikado plays a minor role in this arc, only seen when he came across with Seiji and Mika. After noticing how badly injured he was, Seiji apologized to him about what had happened in the Dollars incident, but Mikado claimed that it was actually the Dollars fault and, since both of them are members, there's no need to worry about it. Right before they parted away, Mika warned Mikado about not hurting Anri, which surprised him. Then, Seiji commented that it was strange for Mikado to talk so freely about the Dollars.
Mikado realizes that, while there are idealists like Kyouhei and his group in the Dollars, there are several others (thugs, gangs, etc.) that would exploit the name of the Dollars to further their own reputations such as those who went rogue during the Toramaru incident. Mikado decides to perform a "cleansing" where he chases down those specific groups that are dragging down the name of the Dollars and "expelling" them from the gang (i.e. beating them up and banning them from the website). He even starts an "invitation only" section of the website for people who he feels he can use for this purpose. After several members were banned, Mikado got a word of another rogue member by the name of Kisuke Adabashi who burned down Ruri Hijiribe's house under the orders of Jinnai Yodogiri.
Mikado, Aoba, and the Blue Squares searched for information on him and they warned Celty, saying that Shinra might be in danger because he was caught on camera several months ago leaving Kasuka's apartment just before Ruri and Kasuka were revealed as a couple and that Adabashi has been targeting those who may be connected to Ruri. This information arrived far too late as Celty found a bloody and beaten Shinra on the floor of their apartment.
Finally managing to corner Adabashi and his followers, Mikado and the Blue Squares confront them about what they've done. Adabashi attacks Mikado, severely injuring him. However, Masaomi arrives in time to save Mikado from getting killed. Before they could exchange greetings, Mikado pours gasoline on Adabashi as he tries to get up. Mikado then calmly lights Adabashi on fire, causing the stalker to run out of the building they were in and into Tokyo Bay. While Masaomi is shocked at Mikado's behavior, Mikado continues to remain eerily calm. He then tells Masaomi that they "shouldn't meet yet", as he is "Still creating a place where Masaomi and Sonohara-san can return."
Dragon Zombie Arc
Masaomi and Anri get worried by Mikado's recent behavior, therefore Masaomi tried to private chat with Mikado, who refused, then left the chatroom.
Kadota's Coma Arc
In the beginning of the arc Mikado is holding a meeting for the Blue Squares with Aoba. He starts looking at the news for the Dollars in front of everyone and sees that a lot of Dollars members are having a huge dispute over Kadota's accident. Mikado is disturbed by the news. Later he finds out that Shizuo has been arrested and put in police custody. Mikado is glad that Shizuo was arrested right after he quit Dollars.Then Aoba told Mikado that Celty was nearby and Celty was nearby the entire time the meeting took place. Mikado was very surprised since he hasn't seen Celty for a long time, and wondered how Aoba had made contact with her. When Celty asks Mikado about his injuries he replies that the 'bad people' did it. While Celty kept on asking him questions Akabayashi entered the room and asked Mikado if he would join the conversation. Mikado is scared at first and then calms down.
Akabayashi asks Mikado if he wants to be allies with the Yakuza. Mikado accepts after a couple of minutes of talking. Then Shuuji walks in and asks Mikado if he could help him find Haruna. Later, Mikado talks with Celty. When Celty asks him what he was going to do with the Yellow Scarves, Mikado replies that he is going to start an all out war. Celty is surprised at the news and tries to to stop Mikado.
Saving Izaya/Haruna Returns Arc
After meeting Shijima and seeing Celty's head on the news, Mikado calls Izaya to test how much the information broker is involved. They also discuss Mikado's recent actions, and Izaya warns Mikado that it is his last chance to step out of 'this world' now that Akabayashi knows Mikado's identity. Mikado asks if Izaya is the one who told Akabayashi his identity and Izaya denies this, though Mikado correctly deduces that Izaya is the one who told Masaomi of his status. However, he actually expresses gratitude for Izaya telling Masaomi because it pushed him to take more responsibility for Dollars. Mikado confesses that his goal is to bring Dollars back to the way it was during the initial meeting he called, and he will destroy all the 'unnecessary things' including the Yellow Scarves and even himself. Izaya is overjoyed at the proclamation because he feels that Mikado is expressing the epitome of humanity, surprised by Mikado's actions, but highly satisfied with them. Mikado further surprises Izaya by revealing that he knows about Izaya's past with the Yellow Scarves and Blue Squares, but he's willing to let it slide for the moment and let Kida resolve it with Izaya. He expresses that he would be happy if Izaya would be on his side in the ensuing conflict but knows it might not be possible.
Mikado is visited at the Blue Squares hideout by Ran Izumii. After Mikado requests to be left alone with Ran to discuss, Mikado demands Ran to leave the Dollars, stating people like him are not wanted. Ran, following orders from the Awakusu Group, gives Mikado a gun.
Final Curtain Arc
Mikado's plan reaches its climax when he confronts Masaomi on the rooftop of Tokyo Hands, near where the original offline Dollars meeting took place.Mikado explains his desire to turn Dollars into an urban legend so that it will constantly be changing and evolving. Masaomi argues with him in an attempt to reach his best friend. As their argument continues it is revealed that Mikado is in possession of two guns, one of which he has already fired at Dougen Awakusu's home. Another gun is fired at the police station in the name of the Dollars, making them the most wanted gang above and below ground in Ikebukuro. Mikado threatens Masaomi with the gun, noting that he doesn't know how to aim and isn't sure what he will hit. Masaomi fights to get the gun away from Mikado. It ends with Mikado shooting Masaomi in the knee. While Masaomi is on the ground, Mikado loses his grip on sanity. He launches into a long rant, shouting about how he would likely shoot anyone or do anything to achieve his goals and that this makes him unnecessary. He comes to the conclusion to shoot himself, and that this will provide himself with the opportunity to see the other side.He pulls the trigger but right before the bullet could hit his skull Celty's shadows stop it, saving Mikado's life.
Mikado seemingly comes to his senses and Masaomi forgives him for everything, taking him from the Tokyo Hands building. At this point they meet up with Anri. As the friends are leaving the scene, Nasujima, a teacher from their school who is currently controlled by Haruna's Saika, comes to attack Anri. Mikado throws himself in the way of the blade, taking the hit for her, and ends up in the hospital. Mikado's parents show up to make sure he's alright. Anri and Masaomi make up the story that Mikado was hurt by a branch during a camping trip. Mikado's parents apologize that their son has caused them trouble and ask them to take care of Mikado before leaving.
Upon waking up from his coma Mikado collapses into a fit of tears.
Mikado is revealed to have been held back a year due to his hospitalization period after the incident at the end of the original series. After watching Yahiro leave the school grounds from the third-floor window, he remembers Masaomi and Anri's faces along with his days spent with them walking the streets of Ikebukuro. He then chuckles, and—turning his back to the window, simply welcomes Yahiro to Ikebukuro and wishes him luck.
It is revealed that he has become a Saika child after being stabbed by Nasujima in the previous series, but the curse has faded over time and has little influence over him. He can use his ability to control the curse to see if there are other nearby Saika children. He is also dating Anri now.
- "Mikado Ryuugamine" is written "竜ヶ峰帝人" in kanji. First, his given name "Mikado" means "emperor." His surname, "Ryuugamine," means "dragon's mountain." The second character "ヶ" is rare for surnames and is often a noble's name, so it sounds classic. It also has five syllables; usually Japanese surnames have three or four syllables. The more syllables it has, the more classic it sounds.
- His mother's name is Hiromi (ひろみ) while his father's name is probably read as Ryuugamine Tatsuya (竜ヶ峰竜也) (there is no official romanization for his parents' names).
- His given name's kanji usually read as "Teijin" instead of "Mikado."
- He has the same name of the European version of pocky.
- He was born weighing 2982 grams.
- He ranked 1st in Raira Academy's entrance test, tying with Anri. Anri has developed a small admiration for Mikado because of this.
- His favorite subject is IT while his least favorite subject is P.E., as he states that he is weak at sports.
- His favorite quote is "Supreme rule of life is to adapt without compromising," the words of German philosopher Georg Simmel.
- According to the character profile card released with DVD vol. 1, his hobby is internet surfing, his favorite food is skewer-grilled chicken in miso sauce, and his least favorite food is "anything that's too hard."
- A man simply known as the photographer who appears in the very first volume of Baccano! appears to live in the apartment right next to Mikado's. The ending of the first volume takes place in present day Ikebukuro as the photographer returns from his vacation in New York.