Master Zen (https://i.pinimg.com/originals/c3/7f/be/c37fbe700baa180527f28c6118fb8476.png), with full name Ryoku Zenobis is quite famous. Even a quick search online reveals his past a sucessfull MMA(mixed martial arts) fighter who later changed to wrestling in the USA, only to vanish completely a few years later. Despite his young looks, he still is 31 years old already, single and suceptible for flirting. He is known for his merciless training methods yet fair grades for those who try ernestly but fall short of his high expectations.