Wombok

Wombok is a fictional character included in the Dragon Ball Super manga and anime. He is the Saiyan Supreme Kai of Universe 10 and serves as both a supporting character and eventually the main antagonist in the Universe 10 saga. His character starts off rather shy, polite and non-responsive. This later changes when learning about the modern existance of the Super Saiyan transformation. Wombok then becomes determined to learn the form from Goku by befriending him. However, he is consumed by sheer power and turns against Goku. With his Supreme Kai strength and access to the Super Saiyan transformations, Wombok decides to gain revenge on the Elder Supreme Kais of Universe 10. 
Wombok learns the first Super Saiyan transformation from Goku. After this, he instantly gains access to the rest of the Super Saiyan arsenal. Although, Goku shows he's still stronger than Wombok by beating him mercilessly. Wombok then tricks Goku by taunting him, sealing his body inside a mystical container. Eventually, he does the same to Vegeta and the rest of the Supreme Kais. 
Piccolo decides to form a team to rescue Goku and Vegeta. This team consists of: Piccolo, Gohan, Goten and Trunks (Gotenks), Majin Buu and Krillin. Together, Majin Buu, Gotenks (Super Saiyan 3) and Gohan face off against Super Saiyan 3 Wombok, whilst Piccolo and Krillin steal the multiverse box. Krillin is successful at stealing it, and Piccolo charges a new technique he learnt training with Whis before the Universe 6 tournament. 
He is later killed by Piccolo's Super Hell-zone attack.