Grimlord was the alter ego of billionaire Karl Ziktor, owner of Ziktor Industries, and the primary enemy of the VR Troopers television series. Grimlord, many years ago, was responsible for the capture of scientist Tyler Steele, and the near death of Professor Horatio Hart, forcing Hart to remain in virtual reality to stay alive. Grimlord, during the same measures taken above, also accessed a source of Tyler's and Hart's experiments in Inter-reality travel, and gained the incredible powers required to access cyberspace.

Upon arriving in Virtual Reality, Grimlord soon assembled a fierce army of mutants and cyborgs commanding them from a place of authority. In the first season, this was the Virtual Dungeon. In the second season, it was the orbiting Virtual Dark Fortress. He also appointed several mutants and cyborgs as authority figures themselves including General Ivar and Colonel Icebot. In perhaps the greatest irony, Grimlord transformed Tyler into Dark Heart. Yet Dark Heart turned traitor after Ryan freed him from execution. When Ryan and Dark Heart confronted Grimlord, he ended up escaping after setting the Virtual Dungeon to self-destruct. When Dark Heart regressed back to Tyler Steele, Grimlord abducted Tyler with his magic as he still needed Tyler for his next plot.

Grimlord, like the Troopers, had a civilian identity and can travel between both realities on a regular basis. He uses a transference orb placed on the desk of his office and chants, "Forces of Darkness, empower me! Take me back to my virtual reality!" The orb sends a current of energy into his body, changing his physical appearance. Upon transformation, he is taken to the throne room of his command center.

Like most heartless supervillains, Grimlord cared very little for his army and henchmen, and generally loses patience with them quite easily when they report a complication or failure. His constant defeats by the Troopers causes a frequent irradiation in enraged eyes and a clenched fist at the conclusion of every episode. Grimlord is not above destroying his own base to kill the Troopers, as displayed three times in the series (twice with the Dungeon, and once with a cave he was temporarily using after the former's final destruction). In the second season, Grimlord attempted to trap Ryan in another dimension just to prevent the Troopers from learning his name in reality. In fact, no one, not even the Troopers or Professor Hart, knew that Grimlord and Karl Ziktor were one and the same.

In the second season, Grimlord underwent a drastic change in appearance and format after self-destructing the Virtual Dungeon for a second time. With barely any footage of his counterpart existing for use anymore, Saban upgraded Grimlord into an American exclusive character and base of operations. Siphoning off Tyler Steele's knowledge of Virtual Reality into an energy prism (which resembled a green crystal), Ziktor discarded his traditional orb, and used this prism to access a whole new army of Virtual creations and a new base of operations called the Virtual Dark Fortress. He now had an appearance that slightly resembled his old appearance with a cape and this form also included Grimlord having a long tail. He was no longer confined to sitting on a throne, and also had the ability to teleport to different places at will. His counterparts from Choujinki Metalder are Gozou Kirihara and Emperor GodNeros.

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