Grimm was born a mutant with the power to control and manipulate plants.  His powers manifested when he was 15 and he soon joined Xavier's team of New Mutants along with Karma, Wolfsbane, Moonstar, Sunspot, Cannonball, and Magik. On one of their missions the team was sucked into limbo where he and his teammates faced Belasco. The team fought and defeated Belasco and everyone escaped except for Grimm. Stuck in Limbo for a year part of his soul was taking by Belasco. He learned a teleportation spell and found a way back to Earth where he found he had gained the power to grow a pair of wings. Months passed until the team had once again found themselves transported to a new place. This time it was Asgard. Seperated from the group he wandered around looking for someone to help him. He eventually found Gaea in the form of a wolf. Grimm saved Gaea from a group of bandits. After this Gaea deemed Grimm worthy and gave him the ability to talk to and control animals.