Simon Harper was the producer of Sentries of the Last Cosmos, an epic science fiction VR game very popular amongst teenagers.
Thanks to the success of the Sentries of the Last Cosmos franchise, Harper became immensely rich and popular. Consequently, he soon lost his grip on reality and started to live out his own fiction. He created a merchandising empire based on his franchise, and cast himself in the role of "The Great Wise One". In his private estate, Sentrycroft, Harper surrounded himself by high-tech machinery resembling of his fictional world.
Harper was bound by contract to share the profits of his game with its writer, Eldon Michaels, but when he failed to do so, Michaels sued Harper for 20% of the royalties. Harper then summoned the game's three highest scoring, but mostly fanatical, players and tricked them into doing his dirty work. He convincing them that his fictional world was real, and invited them to become real-life Sentries, fighting against "The Dark Regent", who was Michaels.
First, he sent them on a "sacred mission" to Gotham's Hall of Records. Believing they were going to destroy a databank infected by the Regent, they were in fact destroying the original of the royalties contract. However, Batman intercepted them and fought them off. He became suspicious of Harper and decided to confront him. At Sentrycroft, Harper casually denied any involvement in the attack on the Hall of Records. Then, he told his Sentries that Batman was an agent of the Dark Regent, who was in fact on Earth disguised as Michaels.
Harper ordered his followers to do away with Michaels, but they balked at cold-blooded killing as among other reasons, Sentries in the game are honor-bound to never kill, and instead they captured him and brought him back to Sentrycroft. Furious, Harper blasted Michaels with lightning bolts from his hands, generated by a special suit he developed. At that point, Batman intervened and told his Sentries about the lawsuit, exposing Harper's charade. He tried to deflect him but Batman threw a bola at his hands, causing the electrical discharge to fry the suit's circuitry. Helpless, Harper ordered his Sentries to tackle Batman, but they turned on him. Harper was presumably brought before justice.
In a way, Bruce Wayne reflected, Harper was just as obsessed as his followers. Where another man might have simply given Michaels his cut and kept the lion's share for himself, Harper was unwilling to give up his place at the center of the fan's universe.
Simon Harper donned a special suit underneath his robes that allowed him to emanate electric bolts from his hands.