Hasga Entolio, a half-elf from the world of elves, possesses distinctive violet hair, yellow eyes, and the characteristic forehead line of half-elves in his universe. As the younger brother of Serge Entolio, he shares a similar style of vest and torn pants. His temperament is markedly hostile and volatile, a stark contrast to Serge's calmer nature, particularly evident in his heated interactions with humans like Haruka Shigure. This hostility frequently erupts into violent outbursts, especially when his honor or Serge's is challenged, often requiring Serge's intervention to restore calm.

His primary ability manifests as destructive magic specialized in shattering seals, barriers, and other magical constructs, defining his role as a spell breaker for the Church. Hasga and Serge serve the Church under coercion, driven solely by the desperate goal of rescuing their mother, Ela of the East, who suffers traumatic experiments at the Church's hands. This coerced service forces Hasga into morally compromising actions, including the kidnapping of Haruka Shigure to leverage against Saitohimea and Taito Kurogane. Despite his aggressive actions, underlying traits reveal a reluctance to harm innocents when not under duress, indicating conflict beneath his hostile exterior.

Hasga's involvement in the human world centers on antagonizing the protagonists to fulfill the Church's demands. Upon achieving their objective and freeing their mother, Hasga and Serge transition from adversaries to allies. They join Gekkou Kurenai's student council at Miyasaka High, marking the resolution of his core narrative arc and positioning him within the main group's subsequent efforts.