On the surface, Zen is known for being a very eccentric and flirtatious character. He will often talk about his looks, praising and complimenting himself for how attractive he his, as well as how talented he is when it comes to singing and acting. Zen tends to compare others to himself when it comes to looks, frequently telling Yoosung to work out to look half as good as he does. Despite this, Zen can become very loyal and caring, especially to those he cares about.In conjunction, deep down Zen self doubts himself, wondering if people only see him for his looks, rather than his talents. He can be easily upset if something affects his career, almost entering a depressive state.