Dragon Face was the sub-leader of the Purple Dragons street gang and through this association an enemy of the Ninja Turtles and Casey Jones. This character was specially created for the 2003 animated series.
Dragon Face, who owed his gang name to his dragon tattoo on the left side of his face, was the acting leader of the Purple Dragons in New York City, after the death of their previous leader in the series' first episode at the hands of Oroku Saki. It's never revealed what Dragon Face's real name is.
He first appeared in the TMNT 2003 series episode Meet Casey Jones where he leads a group of Purple Dragons to fight Casey Jones and Raphael but the other Ninja Turtles came and defeated Dragon Face and his men.
In his next appearance Fallen Angel, he led a group of Purple Dragons to rob a store and later fought with the TMNT and Casey after they left the store. Dragon Face was later seen as a member of the crowd watching the two Purple Dragon initiates (Leo and Raph) fight in the Purple Dragon cage match. He later finds out the Purple Dragon initiates are two of the Turtles but calls them "kung fu lizards" until Raphael tells him they are turtles. He later led a Purple Dragon charge against Leo and Raph but the other Turtles came and defeated Dragon Face and his men.
He was under the direct command of Hun, but was more loyal to the Purple Dragon "cause" than Hun himself, whom he despised secretly because Hun preferred to be the Shredder's subordinate errand boy rather than to make more of the Dragons. Therefore, he began more and more to act according to his own will, whenever the opportunity presented itself, but he was at the end always subordinate to Hun.
The festering resentment in him finally came to explode when the Turtles apparently killed the Shredder in a major confrontation and thus left a power vacuum in the criminal world of New York. The most powerful criminal organizations in the city - the Foot Clan, the Purple Dragons and the Mafia - began to vie for supremacy in the city, which began to escalate into a full-blown gang war. Dragon Face finally saw an opportunity for the Dragons, to work at the top of the food chain, but Hun appeared and led the Purple Dragons to take over New York from the Mob and the Foot Clan. When Karai the adoptive daughter of the Shredder who wanted to put an end to the bloody power struggle, assumed the identity of the Shredder, Hun was ready to submit to his old master again, this was the last straw for Dragon Face, and he challenged Hun in front of the other parties (including the Turtles) which turned into a bitter battle. As Karai was finally unmasked in the action, Hun and Dragon Face allied again against the common enemy, but what happened to Dragon Face after, the events of City at War, is not known.
He hasn't been seen since City at War when he attempted to turn the Dragons against their leader, Hun who called him a traitor, and since then Hun has had complete control over the Purple Dragons.