In the beginning DreamSlayer was believed to be a robotic replicant of a living entity. While being part of the Extremtists he killed more the half of the population of his alternate Earth, Angor. Dreamslayer along with Silver Sorceress, Blue Jay and Mitch Wacky head for Earth. Mitch Wacky was a inventor who was the one that created the robot replicants of his teammates. DreamSlayer kidnapped Maxwell Lord and brought him to the Island of Kooey Kooey Kooey where the inhabitants where mentally controlled by Dreamslayer. Dreamslayer forced Wacky (while in bad health) to work on the robotic extremists. Wacky only managed to fix the Lord Havok robot because he didn't have enough supplies for the others. Dreamslayer realizing now that he didn't need Wacky since Lord Havok was functional, so he broke Wacky's neck. Silver Sorcerecess alongside her Justice League teammates attack Dreamslayer but he mentally controlled the people of the island to attack for him. Silver Sorceress did not want to hurt them so she held back but she died when an arrow hit her in her stomach. But before the Silver Sorceress died she had neutralized DreamSlayer.
Dreamslayer appeared briefly several times once in a Justice League and Avengers crossover where he tried to kill Hawkeye and Flash. Overmaster later used Dreamslayer for evil tasks. Dreamslayer also returned again when tring to plaque Supergirl and the Justice League.
Lord Havok and the Extremists
In the return of the DC Multiverse, Lord Havok and the Extremists are created and are based on Earth-8. In this Universe Dreamslayer appears as a demon who is god of Dreamology (his own religion). In this he tries to get followers that will worship and honor him so that he can find a host vessel. Later Dreamslayer possessed Louie Marino and tried to kill his followers. He was stopped when Lord Havok caste a spell on him that would weaken him. Dreamslayer than left Louie's body and entered the body of Louise the sister of Louie. He believed the she was strong enough to keep the demon locked inside. It's revealed now that Tracer part of the Extremists is in a relationship with Louise.
Powers and Abilities
Dreamslayer is a powerful sorcerer that draws his power from the dimension of terrors. He has displayed the ability to teleport, read minds, manipulate matter, possess beings and fly. He is a wraithlike being and is unlikely to be killed by conventional means.
Justice League Unlimited
Dreamslayer appears in the Justice League Unlimited episode "Shadow of the Hawk" voiced by John DiMaggio. He appears alongside the other Extremists when they attacked a city and battled the Justice League. Dreamslayer managed to subdue both Batman and Vixen, but was trapped in a bubble by John Stewart. He used his pyrokinetic abilities to try and overcome the bubble, but all it did was consume the oxygen inside and render him unconscious.