He is a very bright and kind person who will go out of his way to help the people around him. His main ability is super speed. In the past, Ji-U had no friends because he was afraid that people would discover his powers and those they discovered would treat him like a freak. The first friend he made was a stray cat, which led to his adoration for cats today. His mentor is Kayden Break, who started to live with him. He is friends with Ji-Seok Yu, U-In, and Su-Bin Lee.