Lyca, a lycanthrope commonly known as a werewolf, was discovered by Z-Loan office members during a recreational camping trip. Initially mistaken for a zombie, he attacked Shito Tachibana and Michiru Kita but retreated after Michiru struck him repeatedly with a bag of groceries. Later, injured and seeking refuge, he appeared at the campsite hot springs where Shito and Chika Akat"suki confronted him. Shimotsuki Kuze intervened, clarifying Lyca was a living human rather than a zombie, enabling his escape.

Tracking his blood trail to a cave, Shimotsuki employed her specialized keys to unlock his true nature through an awakening ritual. She then integrated him into the group, provided varied education, and enrolled him at the academy attended by Shito, Chika, and Michiru.

Lyca exhibits intense protective instincts toward Shimotsuki, often displaying aggression toward same-sex individuals due to their shared history. Michiru remains an exception, permitted to pat his head. His olfactory ability to detect the undead proves potentially more useful than Michiru’s Shinigami eyes for identifying zombies.

As the sole survivor of his slaughtered family, he carries their legacy, though details of their demise and his lineage remain undisclosed.