Brennan Mulwray was a thief, until Genomex caught up with him. They were actually pursuing Emma deLauro at the time, as was Mutant X. He declined the latter's invitation to join only to be captured by the former. Upon regaining his freedom, he decided that perhaps the cause of fellow mutants was his concern and joined the fight against those who would exploit them. He loves being a mutant, but is also secretly afraid of his own powers, afraid he might lose control.
Brennan can generate and control electricity, able to throw lightning bolts at will. In fact, it may be he can transform into living, sentient electricity, as on one occasion a mutant who could absorb energy actually merged with him. Exposure to water can short him out if he is using his powers at the time. He is also a skilled martial artist.