Bleak Michael was a former prodigy, a genius when it came to chemicals. At one point he created a toxic nerve gas and brought it to his school to show "the shocking lack of awareness of potential biological terrorism." It was fully functional however and went off, killing twelve students and four teachers. He was sent to Arkham Asylum; that is until he was released by Knightfall and made a member of her Disgraced.
Bleak Michael was created by Gail Simone and Alitha Martinez, and he first appeared in 2012's Batgirl #10. He wasn't properly introduced as Bleak Michael until the following issue.