Real name: Johnny Warren
First appearance: Robin #121
A cruel enforcer working for mob boss Henry Aquista in Gotham City, Johnny Warren became fused with a demonic artifact, gaining tremendous power but also losing a certain amount of self control. He gained the ability to suck the life out of people and many other powers.
He encountered Robin and Spoiler in his attempt to take over Aquista's operation, which left a trail of withered corpses. "Playing whack-a-mole" with Stephanie, he used his glowing power to throw several large objects at her, which she easily dodged. He captured Tim, electrocuting him and threatening to kill Steph and "everyone he ever cared about." Tim pleaded with him to let Steph go to no avail. Spoiler kicked Warlock in the face, allowing Tim to break free, saying, "both of you quit talking like I've got no say in the matter!"
Warlock quickly broke Stephanie's leg, and was about to kill her when Tim began beating him savagely. Johnny fell apart, and Tim freaked out, thinking he killed him, but in reality Warlock has just burned out of juice, and resurfaced later.
Consumed with guilt over Warlock's 'death' and Steph's injury, Tim considered quitting as Robin. Stephanie snapped him back to reality by yelling at him about all the lives he'd saved, including hers.
Warlock later hired Scarab to kill Tim, causing Steph a great deal of trouble when she replaced Tim as Robin.