Yoo-Yee is a skilled martial artist trained in Kung Fu, and is somehow even able to fly. He is Sheen's arch-nemesis, who wants his position as the Chosen One.
He has a fierce desire to be Chosen One of Shangri-Llama. Since Sheen holds that title, Yoo-Yee captured Libby to force Sheen into fighting him. He was on the verge of defeating Sheen to become the Chose One, until Libby acknowledged that she was Sheen's girlfriend. Sheen gained the Eye of the Tiger, which allowed him to defeat Yoo-Yee, just before Cindy delivered the final blow with a Triple Axel Mid-Air Betsy flip.
- Yoo-Yee bears similarity to Liu Kang and Scorpion from the Mortal Kombat franchise.
- Yoo-Yee is the only character in the franchise to be someone else's enemy instead of Jimmy's.
- Yoo-Yee would've returned in season four and re-challenged Sheen to another battle.
- It is unknown why he is not in the League of Villains. It is possibly because he is technically, Sheen's enemy and not Jimmy's.
- He has a unnamed younger sister.