Waylon Jones, also known as Killer Croc, was abandoned and put under the guardianship of his incredibly abusive and alcoholic aunt after his mother died giving birth to him and his father abandoned him, due to his appearance, the result of a combination of body mutation, genetic disorder and rare skin disease he was born with, that only worsened over ations: The Joker.
Croc had no idea what connection Pennyworth had to Batman, but he executed the deed without question, and brought Alfred back to Poison Ivy's Exotica Emporium where four other hostages were being held by the Riddler and the Scarecrow. Batman soon arrived to rescue the hostages and fought with Croc once ations: Medusa Black Mask.
Later in the game, the player has to venture into Killer Croc`s lair, to get the antidote for the Titan poison as plants needed for the antidote grows only in the Killer Croc`s lair. He comes blasting out of the water and then charges at the : Killer Croc, Croc, King Croc, Hydra.
Poison Ivy recruits Catwoman, Killer Croc and the Mad hatter to help her go after Harley. Batman and Batgirl follow to try and do damage control. Director Nick Fury is fucking sick and tired of random costumed weirdos popping out of portals and causing trouble. Joining a traveling circus and adopting the stage name, "Killer Croc", Jones bonded with his fellow carnival workers and felt like he had a family for the first time. Batman soon learned of the antidote's location after his discussion with Poison Ivy in the Elizabeth Arkham Greenhouse at Affiliations: "Black Mask".
In "Almost Got 'Im", Killer Croc is revealed to be a member of the villains' poker game, consisting of Poison Ivy, Penguin, Two-Face and Joker. He tells a story of throwing a rock at Batman as his closest scheme to killing Batman, defending the scheme with "it was a big rock".
The Closing Chapters. Batman: Arkham Asylum’s later half sees several difficult boss fights against some of the Batman’s greatest rivals. The Joker is the most obvious that must be taken down, but opponents such as Poison Ivy and Killer Croc also present Batman with various challenges. Set to join Gotham during season 3 are notable Batman canon villains The Court of Owls, The Mad Hatter, Killer Croc, (maybe) Harley Quinn, Solomon Grundy, and a new grown-up version of Poison Ivy. This is all in addition to the impending returns of Strange, Mooney, Penguin, etc.