Blockbuster was a henchmen of The Joker.
Incident Report[]
Pre-Arkham Asylum Incident[]
Blockbuster was hired by the Joker to pose as Batman and fight Jason Todd, formerly Robin, who had been held captive and tortured for years. Jason had succeeded in overpowering Blockbuster, but after being handed a gun by the Joker, he hesitated, resulting in a frustrated Harley Quinn shooting Blockbuster in the chest, killing him.