- I will enjoy feasting on your bones!
- — Killer Croc src
Waylon Jones was born with a rare genetic disorder called epidermylitic hyperkeritosis, a condition that causes the skin to thicken and flake off in a pattern resembling reptile scales. After the deaths of his parents, Waylon was sent to live with his aunt, who treated him little better than an animal. Every day, for years, young Waylon put up with his aunt's abuse until he finally snapped. He then killed his aunt and fled. For an unknown amount of time, Waylon lived like an animal in the swamps, until the day he met a young blind girl named Betty, who wasn't afraid of him. Betty took Waylon to her home, a travelling carnival sideshow, and introduced him to the various other freaks and performers. For the first time since he could remember, Waylon found acceptance and friendship.
Calling himself "Killer Croc", Waylon found a place in the carnival as an alligator wrestler, grappling with the huge reptiles in a tank of water for cheering fans. For a time, Croc was happy. One day, the carnival owner sold out to another man who moved the show to Gotham City. The crowds were a lot worse, and some of the gawkers were openly hostile toward the performers. Croc managed to catch two punks who were harassing Betty and had them hauled off by the GCPD. A few nights later, the punks returned and detonated a bomb. Croc was thrown into the river by the explosion, his thick skin protecting him from the blast. By the time he hauled himself back to the docks, he discovered most of his friends, Betty included, had not been so lucky.
Now without a home or a job, Croc fell in with the mob as an enforcer, a job that suited him. He found himself in the employ of Black Mask, who was placing a massive hit out on the Batman during Christmas Eve. Croc accompanied his new employer on an attack at Blackgate Prison, where he slaughtered numerous guards, eventually helping Sionis drag police commissioner Gillian Loeb into the gas chamber, where he was executed. Batman arrived on the scene too late to save the commissioner, but attempted to stop Black Mask's escape, only for Croc to intervene, forcing Batman to fight him. While Jones possessed far greater strength and a crushing jaw, Batman's quick wit and gadgets allowed him to overcome Killer Croc, dangling him over the edge of a cliff for an interrogation. Croc revealed that Mask had hired seven other assassins and mercenaries to take Batman down that night, but before Batman could extrapolate further data, Captain Gordon arrived, forcing Batman to retreat and leave Croc to be taken in by the GCPD. Batman would later tell Alfred that the source of his information was a "human-shaped crocodile", to the Butler's mild amusement and surprise.
While this was the first of their encounters, it would not be the last, as over the years Croc would find himself in and out of Arkham Asylum, escaping to wreak havoc on Gotham, only to be caught and returned by Batman. During one of these escapes, he devoured the hand of Guard Aaron Cash.
Killer Croc was one of the criminals that broke out during the Joker's takeover of the Asylum. But Jones didn't exactly work with Joker, and didn't seem to have a specific place in Joker's plans. When Batman journeyed into the sewers of the Asylum, Croc was there, stalking Batman the whole way, sometimes coming close to achieving his goal. But in the end, a well thought out plan, and a bit of well placed explosive gel was enough for Batman to put an end to Croc's hunt.
Killer Croc met with Batman shortly in sewers of Arkham City. The Bat told Croc that he had no intention of fighting him, to which Killer Croc replied that he could smell death upon the vigilante and that it won't be long before he feasts upon his corpse. Returning to the waters, Croc decided to challenge Batman another day.
After Arkham City
After the Joker's death, Harley attempted to fulfill her puddin's final will by hiring Croc to guard the clowns' last remaining stash of Joker venom antidote. Jones, accepting Harley's offering of barrels of fish for a job that he would probably do for free anyway, waited in the sewers for weeks until Batman was lead to his location.
As planned, the Bat discovered the antidote stash, intending to use some of it on Commissioner Gordon, who had been infected as part of Joker's final will and testament. There, he was ambushed by Croc, losing his utility belt in the process. Jones was about to kill Batman but was distracted long enough by Aaron Cash to be subdued by Batman's last remaining Freeze Grenade. 
At some point, Croc set up a lair under the old Gotham Lighthouse. He was eventually captured by agents working for the warden of Iron Heights penitentiary. On the airship prison, Croc was tortured without end by the warden's scientists, the trauma only causing his mutation to grow worse. Finally, Croc managed to break free and lead a riot that caused the airship to crash in Gotham Harbor. By the time Batman caught up to him, Croc and his fellow test subjects had strapped the warden into the same medical rig he had used on them. After a fierce fight, Batman defeated Croc and shipped both him and Iron Heights' warden to the GCPD.
- Unique Physiology
- Amphibian: Although not officially able to breathe under water, Croc is able to hold his breath underwater for an incredibly long time. This allows him to hide until potential prey come by.
- Enhanced Senses: Jones is able to feel movement while underwater and find his prey using this movement. He repeatedly states that he has memorized Batman's scent and thus knows when the Dark Knight is near; this prevents Batman from sneaking up on him.
- Superhuman Strength: Croc is capable of lifting things up to the size of a car without much effort. Because of this inhumane strength, Batman never attempts to beat Croc in hand-to-hand combat, often outwitting Croc instead.
- Superhuman Durability: Thanks to his regeneration ability, it's almost impossible to harm Croc, considering that back in Origins, Batman had to trick him into getting in the blast radius of exploding tanks. By the time of Knight, it took the combined efforts of Batman and Nightwing to render Croc unconscious.
- Superhuman Speed: Croc is fast in the water, being able to almost keep pace with Batman, who was running away on platforms on the water. By the time of Knight, Croc lost his speed due to his body structure becoming more like a crocodile; he now has to run on all fours.
- Claws: Croc's nails have become sharpened claw, capable of being able to break through metal, possibly even the TYGER vault.
- Fangs: Croc's teeth became sharp enough to rend flesh.
- Regeneration: Waylon's genetic mutation has gifted him with a healing power that is almost unable to be charted. Minor lacerations disappear within minutes and he has fully regenerated an amputated hand within a week.
- Adaptive Mutation: As a result of his regeneration ability, Croc's body adapts to whatever harmed him. This unfortunately speeds up his mutation into a crocodile creature, leaving him less and less human.
- Monstrous Appearance
- This version of the character is exclusive to the continuity of the Arkhamverse video game series and is an adaptation of Killer Croc. The original character was created by Gerry Conway and Gene Colan and first appeared in Batman #357.
- For Arkham Asylum, Killer Croc was voiced by Steve Blum. For Arkham City, Killer Croc was voiced by Dee Bradley Baker. For Arkham Origins, Croc's grunts were voiced by Khary Payton.
- This makes Croc the character with the most voice actors in the Arkham series.
- 19 Appearances of Waylon Jones (Arkhamverse)
- 6 Images featuring Waylon Jones (Arkhamverse)
- 1 Quotations by or about Waylon Jones (Arkhamverse)
- Character Gallery: Waylon Jones (Arkhamverse)
- Batman: Arkham Knight #2
- Arkham Origins Artbook