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. He is also dating Anri now. 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. 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. Initially, the joke went as planned and people started joining the group despite it being a little more than a forum. Mikado, Aoba, and the rest of the delinquents arrived at an abandoned factory warehouse. Mikado then realized that Aoba was correct but he didn't know why he smiled in the first place. As the battle rages around them, Masaomi punches Horada one last time before falling unconscious. Mikado states that he never noticed anything strange which seems to satisfy Mika's curiosity.
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, Anri, and Masaomi soon start regularly hanging out with each other and attempt to get to know each other better. 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 several thoughts swirl around in Mikado's head, Aoba draws attention to the countless messages left by other Dollars members. The "black emotions" returned, this time aimed at himself for being so useless at such a crucial time. Aoba asks Mikado if he was looking into the incident in Saitama.
The men shove the girls into the back of the van and drive off, leaving a few of their friends (including At Raira, they can see Kyouhei and Chikage fighting off in the distance and the kidnappers and the girls approaching slowly in their van. After several members were banned, Mikado got a word of another rogue member by the name of 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. Mikado, in shock, asks Celty to take him to see his friends. Mikado is a member of a chatroom under the handle "TarouTanaka" and often chats with two other users, "Setton" and "Kanra." Izaya Orihara and Aoba both state later in the novels that they have underestimated Mikado. The next day, as Mikado continues to worry, Masaomi decides to take him to see Later in the day, as Mikado and Anri are about to leave, they are stopped by one of Anri's bullies with her Mikado senses danger and parts ways with Anri, leading Izaya and the Black Rider towards a more secluded area. Masaomi goes on to say that Dollars is in danger but isn't sure what the reason is. Mikado confirms that he was, but is shocked when Aoba casually admits that "We did it."
Mikado Ryuugamine (竜ヶ峰帝人, Ryuugamine Mikado) is a major protagonist who moves to Ikebukuro at the start of the series at the invitation of his childhood friend Masaomi Kida. Mikado agrees to let Celty meet the girl but goes inside first to explain the situation so she doesn't panic. Mikado Ryūgamine is the one of the main protagonists of the light novel and anime series Durarara!!!. Mikado's physical appearance is one that does not stand out from a crowd. Later he finds out that Shizuo has been arrested and put in police custody. Mikado runs up to them and apologizes as the leader of the Dollars. 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. Aoba and Anri agree to meet the next day.
As Mikado thinks of a solution, he gets another disturbing text message on his phone. Mikado initially tried to convince others on the forums to put a stop to the criminal activities but was mocked as a result. Mikado's parents show up to make sure he's alright. He tells the others to stop as a fellow member of the Dollars but gets insulted and kicked as a result.
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. Upon waking up from his coma Mikado collapses into a fit of tears. While Mikado is sad that he left, he and Anri resolve to give Masaomi a proper welcome when he decides to come home. 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. 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. He even starts an "invitation only" section of the website for people who he feels he can use for this purpose. However, the group continued to grow exponentially, even after they stopped giving the password. 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. 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 himself felt small and insignificant. As this fact dawns on him he gets pinned down by several thugs from Yagiri Pharmaceuticals who interrogate him about the girl's location. While he doesn't show it fully until the end of Volume 6, this darker half of Mikado is hinted at in various events throughout the light novels.