Identity Status: Public
Maritual Status: Single
Last Known Residence:
Narrows Island Federal Penitentiary
In Congola, 1975, Hannemaier was chemist who sold stimulants to mercenaries; becoming acquainted with the likes of Slade Wilson (aka Deathstroke).
Imprisoned in a prison nursing home in Gotham City, Hannemaier helped Slade refine his serum to prevent users from becoming insane.