Some TMNT stuff was always meant for grownups.
Before the Shredder New York was ruled by Hun and the Purple Dragons. Like his 2003 counterpart Hun and the Purple Dragons burned down Casey's father auto shop, which caused Casey to go one on one against Hun. With his incredible strength Hun nearly beat Casey to death in front of his mother, until Casey managed to pull out a knife and stab Hun in his left neck which caused his left eye to go permanently blind, which caused Hun to go in a rage as he lifted Casey and slammed him face first, which put Casey in a deep coma and on life support.
The leader of the “Black Dragons”, apparently cut a deal with Officer Miller, which resulted in Hun being locked up and allowed him to gain control of the Purple Dragons. He then helped the Purple Dragons’ one-time-rival, the Shredder, wipe out the group, turning them into the Black Dragons: a gang subservient to the Foot Clan. When he was released from prison Hun silenced the Black Dragon leader, then wipes out the Black Dragons, declaring his intentions to rebuild his criminal empire.
Hun was created especially for the 2003 cartoon series. Initially, Peter Laird was not fond of the character, but later declared that he was one of his favorite new characters created for the series, as Hun was further fleshed out. Laird hinted for some time that Hun may make his way into the Mirage universe. On August 6, 2008, Tristan Jones confirmed that Hun would make his way into Tales of the TMNT #56 - a re-tooled version of his scrapped character Copperhead, who in turn, was based on Hun from the beginning. Jones' blog revealed Hun's full name in the comics to be Hunter Mason.
Hunter Mason has appeared in the following comics: