Ryosuke Kaihara

Ryusuke (竜介, Ryūsuke) is an obsessive fan of Ai Hoshino whom he killed after learning that she was pregnant with twins before he killed himself to avoid being arrested for murder.

Plot
After Ai Hoshino announced that she was pregnant with twins, Ryusuke was enraged by saying "You liar... To think you have a brat... Why... You deceived me..." and he later murdered Gorou who was giving chase (although it is not fully confirmed whether or not Gorou was stabbed). Right after he killed Gorou, Ryusuke went straight to Ai's apartment and killed the idol by stabbing her in the stomach while giving her a bouquet of flowers. As Ryusuke begins to insult Ai who starts to bleed, she weakly tells him that she wanted to love her fans, she remembered his name and she still kept a trinket that she gave him. Hearing those words caused Ryusuke to run away in horror and anguish.

In Chapter 10, Ai's death was announced to the public and it was later revealed that Ryusuke committed suicide (through unknown means) possibly in his apartment. Because Ryusuke was already dead, the investigation revolving around Ai's murder and the killer (Ryusuke) responsible for it has ended instantly.

Etymology

 * The name Ryusuke means "dragon" (竜) (ryu) and "help, assist" (介) (suke).

Trivia

 * It is theorized that the reason why Ryusuke committed suicide was to cover up for the same person who leaked Ai Hoshino's address information to him.