When Professor Gerald was trying to complete his Ultimate Lifeform project to cure his granddaughter Maria Robotnik's Neuro-Immuno Deficiency Syndrome, he found barriers to his research he could not overcome without outside help. Making a deal with Black Doom, he extracted some of Doom's blood to help him finish the process. The result was Shadow the Hedgehog, the Ultimate Lifeform with the abilities granted by Gerald's process and also with a measure of Doom's own power, granting Shadow his Chaos Control abilities. Black Doom afterwards departed, vowing that he would make his return fifty years later, prompting Gerald to modify Shadow so that when the time came Mobius would have him for a protector. (StH: #171)