Chase Young

From Xiaolin Wiki

Chase Young is a former Xiaolin Monk, close to being a dragon, who fought with Grand Master Dashi; however, after the capture of [Wuya], [Hannibal Roy Bean] persuaded him into drinking The Lao Mang Long Soup, which is an ancient Heylin potion that once drank turns the person to the Heylin Side. After he became evil, Chase threw Hannibal into the Ying-Yang world, trapping him there.

1500 years later, Chase becomes interested in the skills of which Omi, dragon of the water, possesses. He thinks of a plan to bring the young monk over to the side of evil, because he believes one day Omi will be strong enough to defeat him and thinks his skills belong to the Heylin side more. After bringing Omi to the dark side, by tricking him into going into the Ying-Yang world without the other yo-yo, Chase begins the 1000 years of darkness.

After the other Xiaolin Dragons give back Omi's chi, Chase turns Omi into a cat and obtains his [dots], but is soon defeated after a Xiaolin Showdown for Omi's freedom. 

He isn't seen as frequent through the rest of the series, but is known to be able to transform into a lizard like creature, and is weakened by the [Heylin Eclipse]. 

He was introduced in the second season, trying to turn [Dojo] into soup. (Season 2 Epsiode 11, Master Monk Guan)