Durarara!! Kokinzoku-hen

As Izaya Orihara wildly enjoys holding all the information about Ikebukuro's main players, Mikado Ryuugamine and Masaomi Kida stay by Anri Sonohara's side while she recovers. However, Kida seems to be faking a smile. Enraged by the circumstances that led to Anri's harm and his own helplessness, Kida returns to the world he vowed to never come back to after Izaya interfered with them—the Yellow Scarves gang.

Once the Yellow Scarves' leader, Kida knows that many of his old team members may now be a part of the Dollars, but they are losing their trust in the group's misdirected ideals. With the power of the Yellow Scarves' unwavering loyalty behind him, Kida swears to clean up Ikebukuro's streets of all wrongdoers, especially those in support of the recently faced criminal, the Slasher. But his aspirations and determination are put to the test, as Izaya is not the only one powerful enough to stand in his way.