He is the younger brother of Ji-Yeong Yu, the CEO of Shinhwa Association.

He is one of the most powerful, if not the most powerful, awakened person in his age group in South Korea.  There are only a few teenage awakeners in Korea that are able to rival him. Like his sister, his awakened power is aerokinesis. 

He is friends with U-In, Ji-U Seo and eventually Su-Bin Lee.

Jiwoo is a kind-hearted young man who harnesses the lightning quick reflexes of a cat to secretly make the world a better place – one saved little child or foster pet at a time. Kayden is a secret agent on the run, who finds himself stuck in the body of a…um…decidedly fat old fluffy cat. Together, armed with Jiwoo’s super powers and Kayden’s uber-smarts, they’re out to fight those forces who would let evil rule this world. That is, if they can stand each other long enough to get the job done.
<br><br>(Source: WEBTOONS)

Ji-Seok Yu