Takashi

Takashi is a thug and one of Youko's boyfriends.

Mika Harima Arc
Takashi and Youko confront Mikado Ryuugamine as he and Anri Sonohara leave school together. He threatens Mikado for the whereabouts of Izaya Orihara, who had smashed Youko's cell phone the day before, but without warning he is kicked to the ground by Celty Sturluson and subsequently jumped on by Izaya.

Saika Arc
An image of him is shown in episode 15 on a cover of the tabloid Tokyo Warrior with Hiroshi.

Toramaru Arc
Takashi is among the group of Dollars members who kidnap Non, Rio Kamichika, and their friends to use as hostages against Chikage Rokujou and the Toramaru bikers. When confronted by Mikado as they are taking the girls away in a van, Takashi is among the three who stay behind to beat him up. Takashi enjoys beating on Mikado, treating it as a revenge for the incident a year prior when he had confronted Mikado and been knocked out in one blow by the Black Rider. By the time Mikado remembers him, Takashi deals him a kick to the head that knocks him unconscious.

Trivia

 * The anime's English subs spell his name "Takeshi."