Ansa Arishin is one of the two main protagonists in the series, serving as the calm and level-headed counterpart to his more impulsive best friend. He is characterized by his serious and thoughtful nature, often showing genuine concern for the well-being of those around him. Despite his typically earnest demeanor, Ansa possesses a contrasting side to his personality, one that allows him to effectively employ a puppy-dog eyed look to get his way.

His background establishes a long-standing bond with his partner, Kaito Aen, as the two have been close friends since their middle school days. This deep-seated friendship is a core part of his character, as he greatly admires Kaito’s ability to act and speak without hesitation, particularly in situations where Ansa himself might feel unable to do so. Ansa’s personal interests and skills include playing futsal, tending to decorative plants, and a notable proficiency in darts. He also has a particular fondness for the savory egg custard dish, chawanmushi.

In the story, Ansa is chosen to become a Q-Former, a savior entrusted with the critical mission of saving Tachikawa from annihilation. To achieve this, he and Kaito must work together to unleash the energy of the Q Stone by defeating sixteen servants and releasing sixteen seals. His role is defined by his partnership with Kaito, as they navigate these challenges alongside their senior, Tokine Amino, and another ally, Hinata Takaragawa. Throughout the narrative, Ansa looks up to Kaito as someone who can do and say things that he cannot, highlighting a dynamic where Kaito’s boldness complements Ansa’s more reserved and considerate nature.