Dark-Crawler was once known as Night-Crawler and was an ancient enemy of the Undying Ones. A cult worshiping the Undying Ones sent the Hulk to his dimension hoping the Hulk would destroy him. To motivate the Hulk to fight, the Undying Ones sent an unconvinced member, Barbara Norriss, knowing that the Crawler would attack her. The battle that followed destroyed the Crawler's scepter and his realm and he was sucked into the Undying Ones' dimension. Once there, the Crawler battled the Undying Ones up until the moment where their plan to invade Earth was spoiled - meanwhile, the Hulk escaped with the help of the Undying Ones' prisoner, Dr. Strange, and thanks to Norris' sacrifice staying behind.
Defeating the demons and their leader the Nameless One and became the ruler of the Undying Ones changing his name to Dark-Crawler. Eventually the Nameless One was again shown to be in control of the undying ones so his fate is currently unknown.
Meanwhile, the villain Leader discovered Hulk's past encounter with the Crawler. The Leader included the Crawler in an array of simulated super-villains he sent against the Hulk in an attempt to cause him a heart attack.