Shu Aozaki

Shu Aozaki (青崎柊, Aozaki Shu), also known as the "street fighting executive" and the "Blue Demon" / "Blue Devil" of the Awakusu-Kai, is a high ranking member of the aforementioned yakuza group and is the fierce rival of his counterpart Akabayashi, who is regarded as the Awakusu's "Red Demon."

Characteristics
Aozaki is said to be 190 cm tall with wide shoulders and large bones. He has "muscles and fat combined in perfect proportions on his body" with an air like that of a predatory animal and wears a suit tailored unfortunately only to his height that "looks like it could burst at any minute". He is also identified by the various scars marring his face which are known to have been put there by Kadota's father.

Aozaki and Akabayashi have shared a mutual rivalry even before Akabayashi joined the Awakusu. However, this rivalry is overshadowed by Aozaki's complete loyalty towards the Awakusu as well as its current leader, Dougen Awakusu. Aozaki states that he doesn't intend to settle the score he has with Akabayashi anytime soon and even warns Akabayashi of any of his old colleagues who want to take revenge for Akabayashi killing their boss. Even though he states that he is loyal to the Awakusu, Aozaki is one of many in the organization who oppose the fact that Mikiya Awakusu, Dougen's second son, will inherit the organization mostly due to Mikiya's lack of any note worthy achievements.

Being rivals, Aozaki and Akabayashi tend to be near polar opposites of one another. Where Akabayashi tends to fight on his own, Aozaki usually has subordinates to back him up. Also, while Akabayashi is adapt at using new technology, Aozaki barely keeps up with it and only knows how to use the basic functions of his cell phone and computer.

Dollars and Blue Sqaure Arc
After the bodies of the three Awakusu members were found, Aozaki, along with Shiki, Kazamoto, Akabayashi, and Mikiya hold a meeting to discuss what to do with the prime suspect, Shizuo Heiwajima. When the prospect of Shizuo being framed is brought up, Aozaki is one of the people Shiki considered to be the most likely to orchestrate such an event. The reasoning is that if three members were killed under Mikiya's command then it would give a sign to other organizations that the Awakusu are at a weakened state with their new leader, thus discrediting Mikiya. This suspicion is later proven to be false once it is revealed that the Russian mercenary, Slon, was really the killer.

Akabayashi and Aozaki are later sent to deal with Slon and Vorona who have been hiding out in a construction site. One of Aozaki's subordinates shot Slon in the legs while Akabayashi took care of Vorona. Aozaki takes Slon back to the Awakusu's headquarters while Akabayashi hands Vorona over to Simon, Egor, and Denis.

Mizuki Akabayashi
As stated earlier, Akabayashi and Aozaki have shared a long and fierce rivalry that has been placed in a standstill since they are both part of the same organization. Although Aozaki hates Akabayashi, this hatred seems to stem from professional pride if anything else. Aozaki frequently warns Akabayashi of old acquaintances seeking revenge and actually manages to have a (somewhat) civil conversation with him when discussing important matters. Although the two do work rather well together on missions, it can be safely assumed that, should Akabayashi ever betray or leave the Awakusu, Aozaki would pounce on the chance to resume his rivalry with him.

Trivia

 * The group of thugs attacked by Shizuo in Sayaka Sonohara's bakery in episode 7 was apparently Aozaki's group.