@Z3RO180: Dick also converted his youngest daughter and heir to the throne into a hero under Slade's own watch. He despised him for that which is the reason Bludhaven no longer exists. Deathstroke dropped chemo on the city to get back at him for his daughters(and his own) betrayal.
He dropped it before she actually converted mate. After Nightwing taught her and took her under his wing, but before Slade dropped Chemo on the city.