Lyca

A werewolf who has been alive for a long time. Raika (Lyca in the English subs) had lived through the deaths of all his kin, and so was was left to live in a cave, surrounded by bones, all by himself. He made his first appearance in Volume 3, Payment 18, when the main characters were staying at the hot springs. The main characters made their way to Raika's cave, where Kuze Shimotsuki tamed him with mysterious powers. She took him back to the city, and he was eventually sent to Z-Loan, under the belief that experience would make him stronger. Raika wished to be stronger for the sake of protecting Shimotsuki.
Raika also begins going to the same school as Michiru, Chika and Shito. He learns human speech, but his knowledge is limited, as demonstrated by his short sentences and occasional wolf growls. He lets Michiru pat him on the head, but bites people he doesn't like, or people who treat him like an animal. Raika also shows a certain protectiveness of Shimotsuki.
Before Shimotsuki named him Raika, he was dubbed "Pochi" and "John" by Chika and Shito. Shito also describes Raika as always being alone, as if comparing Raika to himself.