Greg is a young mutant known as Blowhard and he was a member of the Children of Heaven, which was a cult run by a telepathic mutant named Phillip. Phillip used the children in his halfway home for pretty crimes, drugs, and pornographic displays.
Greg was the leader of the boys who found Michael when he first arrived in New York City and brought him to meet Phillip. Phillip assigned Michael to room with Greg, who took great delight in being mean to the younger boy. First teasing him for being innocent of the world and then showing him a pornographic movie with Beth in it. Greg knew he had a crush on the girl and it amused him to see the boy hurt by the movie.
Later, when Archangel broke the cult up, Greg called for some other mutant children to defend Phillip from the more powerful mutant. However, the children were no match for Archangel. The end of the cult came when Phillip was telepathically attacked by Beth and was taken away by the police. Shortly after Greg left the Children of Heaven to be on his own.
Greg's subsequent fate has yet to be revealed. Also it is unknown whether he retained his mutant powers after the events of M-Day.
Powers and Abilities
Unknown: While Blowhard was known to be a mutant, he did not demonstrate any powers.