Before his fall from grace, Achilles Milo was a renowned chemist, a cunning criminal and a long-time foe of the Batman. His diabolical schemes included: subjecting Batman to a drug that made him afraid of anything bat-shaped, gassing Batman with a compund that made him lose his will to live, manipulating the werefolf-like Anthony Lupus into doing his bidding, taking control of Arkham Asylum, and attempting to make Batman insane with yet another gas. In the last case, Milo was himself subjected to his chemicals, which rendered him insane and earned him a cell in Arkham. Milo has since been released but is but a shadow of his former self. More recently, Batman sought him out to make him provide information given to him by the Joker, after which a trembling Milo declared his retirement from anything criminal.