Zan Amaru partners with the Beast Knight Akitani Inachika as his familiar. He manifests as a large swordfish whose imposing appearance can intimidate others. Aware that his physical form might startle people, he consciously adopts a gentle demeanor during interactions and frequently offers advance warnings about his appearance to prevent alarm, demonstrating a considerate nature. His origins, personal history, and development remain unexplored. The character does not undergo significant changes or arcs. The narrative primarily positions him as a supporting figure to Akitani.