Ikuto's Guardian Character, created from his desire to become free like a stray cat. Yoru carries a strong resemblance to a cat - with cat ears, a tail and claws. He also has yellow eyes and dark purple hair. He wears a sleeveless black leather shirt and a silver cross necklace. His name means "night" in Japanese.
Yoru is very mischievous and likes to taunt the Guardians and their Guardian Characters a lot. He especially likes to steal Kiseki's crown, and he also shown an interest in rapping. He also fights much with Il, Utau Hoshina's Guardian Character, but he usually loses. When he is around Ikuto, he usually ends up acting somewhat of a little brother to him. Yoru is often heard saying "nya" at the end of each sentence. Yoru is also selfless when need be, as he turned to the Guardians for help saving Ikuto when he couldn't do so on his own.
The Shugo Chara! Encyclopedia! describes Yoru as someone who's "constantly getting into trouble", but "always helps Ikuto when he's in a jam".