Un-Wol

He was the master of Chun-Woo Han and Ryuji. After achieving the Black Origin Threshold the Martial Arts Alliance banished him to a life of meditation and solitude in a cave while he tried to figure out a way to solve the problem of this technique. He was always calm and composed, and did not hold a grudge against the elders that exiled him. Despite almost never showing emotions, he is very caring as he expelled Ryuji as a disciple and killed himself to protect both Ryuji and Chun-Woo Han respectively. He is also very moral, as he told off Chun-Woo Han when his student made the wrong choices in using martial arts to hurt others.

(Source: The Breaker wiki)