Real Name: Jonathan Castle
Aliases: Jack. Gorilla With The Human Brain.
Known Relatives: Unknown(father), Unknown(mother)
Enemies: Hawkwing, Marionette, Patrioteer, Shadow Lady.
Base of Operation: New Gateway City
First Appearance: MAXIMUM JUSTICE #2
Modern Appearance: WHC COMICS PRESENTS: REBIRTH #2
History: Drunken Jack Castle was both a assistant to a rogue scientist. He rendered unconscious by the mad doctor, so Castle would not reveal the nature of the doctor's experiments to Elsa, the doctor's niece. Castle's brain was removed and then placed into the body of a Silver-back gorilla. When he awoke from the surgery, he was enraged. Seeking revenge, he killed the rogue doctor. Now he the doctor's other surgical assistants, hoping to be cured of his affliction.
Powers & Weapons: Gronn possesses human intelligence and is an experienced surgeon and inventor. He possesses the superior strength, agility, dexterity, and other abilities of a massive, Silver-back gorilla.