Wawawawa!! is the fourth chapter of the Dollars/Mika Harima Arc.
Izaya and Mikado exchange greetings briefly before Izaya has to leave for a meet up with someone. After he leaves, Masaomi warns Mikado of how dangerous that man is, but Mikado only seems to have only been even more intrigued.
Elsewhere, in a karaoke room, Izaya is with two young girls who wish to commit suicide and asks them what will happen after they die. He indulges them with their conversation on the afterlife but is ultimately disappointed by their naive conception of death. The two women realize too late that the man they knew as 'Nakura' had lied about wanting to commit suicide with them, to which Izaya plays with their emotions and ideologies.
Izaya: "To our first meeting and our eternal farewell to this world."