After an attempt to control her son's body to kill Dick Grayson (who was acting as Batman at the time), Talia al'Ghul is forced to disown her son Damian Wayne, who has chosen to follow his father's path as a crime fighter. As she bids farewell to her son, she makes sure to show him that she's already cloned him, in an effort to create a new son who she can mold to her desires. Talia would later take the young clone to an illegal bio-genetic factory, where the clone would grow at an accelerated rate, and be birthed from the carcass of a whale. It was at this factory that The Heretic became a killing machine.
The Heretic was created by Batman scribe Grant Morrison.
Major Story Arcs
After the clone known as the Heretic was born, both Batman and Damian Wayne come in contact with him shortly after the forming of Batman Incorporated. Damian is the first to see him, where the Heretic tells him that he will eventually know him, but not yet, then disappears. He's later seen at Talia's side by the time that Batman and his allies realize she is the true leader of Leviathan. When Talia moves in on Gotham City, the Heretic accompanies her as her personal muscle and body guard. He later takes on many of Batman Incorporated members singlehandedly, killing Knight in the process, while defeating Batman himself.
Talia gives him the world-bomb trigger to guard. He arrives on the scene at the exact wrong moment as Robin and Nightwing try to reach the higher levels of Wayne Tower. He takes out Nightwing with one move, then fights Robin. Robin puts up a lethal assault, but thanks to Leviathan foot soldiers shooting at him, The Heretic gains an advantage and eventually stabs Robin through the heart with a sword taken from a display case.
Batman arrives on the scene and is horrified to discover his son is dead. Enraged, he attacks the Heretic with the help of Nightwing, but the man-monster easily crushes them both. Recovering Damian's body, they flee. Meanwhile, the Heretic returns to Talia's side, where she berates him for killing Damian without waiting for her command. He replies that he did not need her command, having developed the ability to observe, assimilate knowledge and arrive at conclusions independently. He declares that he is Batman now, and decides that Gotham is his by right.