Kyōkai-san is a supporting character introduced in the second season of the anime Active Raid. He serves as a mechanic and technician for the Willwear powered suits used by Unit 8, the special police unit at the center of the story. His primary role is behind the scenes, handling the maintenance, adjustment, and technical support of the Willwear equipment. Because of his expertise, he is often called upon to provide technical opinions and solutions during operations.

His personality is described as somewhat shadowy and reserved, fitting a behind-the-scenes supporter. At the same time, he has a big-brotherly demeanor, being approachable and relied upon by the members of Unit 8 for his practical knowledge and steady presence. He does not seek the spotlight and instead works quietly to ensure the team’s gear functions properly.

In terms of background, little is explicitly revealed about his past, but his position as a Willwear technician implies a deep familiarity with the advanced armor systems used by the unit. His motivations center on supporting his colleagues through his technical skills, contributing to their success in combat without directly engaging in frontline action.

His key relationships are with the field operators of Unit 8, particularly those who pilot the Willwear suits. He interacts with them during briefings and maintenance scenes, offering advice or adjustments. Over the course of the second season, he remains a consistent and dependable asset, though he does not undergo significant personal development or major storyline arcs. His notable abilities include expert knowledge of Willwear mechanics, the capacity to perform rapid field repairs, and the technical insight to optimize the suits for different mission parameters.