Son of a Yakuza family. He's intelligent but not an adept fighter. He likes sweet things, wants to marry a Yamato Nadeshiko and says he's the kind of person who has to do it absolutely correctly when he puts his mind into something otherwise he can't be satisfied.

Raku once got amnesia. He tried to save Chitoge from a wild ball that unintentionally aimed for her head. Unfortunately, it hit his head mercilessly. He was unconscious and then woke up a second later. He did not recognize anyone, even though all of his friend were beside him. He became a really sincere person. He charmed everyone who talked to him—even Chitoge, Tsugumi, Tachibana, and of course Onodera. During his amnesia period, he stayed at Chitoge's mansion. After some quarrel with Chitoge, it seemed like he hinted about the one who holds a key. It was also unclear though because he immediately regained his memory. The hint regarding the girl who holds the key to his locket is "the girl's eyes were either brown or black but not blue."

In the end, Raku realises that he has feelings for Chitoge, rather than Onodera. While Onodera confesses to him, and turns out to be the girl of the promise, he rejects her confession. He tells Chitoge that he loves her, and she confirms that their feelings are both mutual.