#justifiers

Powers

Regressive Atavism: Killer Croc is afflicted with what seems to be some form of regressive atavism, meaning he has inherited some of the traits of ancestral species of the human race. Over time the primal reptilian part of his brain gains more control of his psyche.

Regenerative Healing Factor: He has superhuman regenerative powers, able to heal even lost limbs.

Armored Skin: His skin has hardened to the point where it is invulnerable to most forms of abrasion and even high caliber weapons fired from a distance.

Superhuman Strength: He has grown so physically powerful and quick over the years that Batman has had to resort to planting explosive devices on Croc's chest to knock him unconscious. He has also been able to rip a large bank vault door right off its hinges with ease.

Superhuman Speed

Enhanced Senses

Claws

Fangs

Abilities

Wrestling: Croc has some experience at street fighting and wrestling. Swimming: Croc is an expert swimmer and can hold his breath far longer than normal humans.

Weaknesses

Diminished Intellect: Killer Croc's mind, once possessing above average intelligence, has now lessened greatly due to his advanced mutation level and the specialized virus designed to advance it created by Hush. He is a high school dropout, but has proven to be moderately capable of organizing thugs in small-time racketeering operations. He is usually hired by other villains as muscle or as a hitman, as he is at least intelligent enough to follow instructions.

History

Killer Croc, also known as Waylon Jones, is a high profile criminal and one of Batman's most challenging adversaries. Croc is best known for his reptilian appearance due to his medical condition, which slowly transforms him into an anthropomorphic reptile.

Origin

Waylon Jones was born in a slum in Tampa, Florida. He was born with a medical condition that caused him to grow progressively more like a crocodile, hence his name. His mother died in childbirth, and his father abandoned him. Waylon was raised by his aunt, but her persistent drinking prevented him from growing up in an ideal household.  As a teenager, Croc had no friends, and was the object of ridicule of those who knew him. By the time he reached adulthood, Waylon found work wrestling alligators as part of sideshow carnivals, where he earned the name "Killer Croc". Croc soon realized that there was more money to be made in crime, so he set out to become Gotham's most powerful underground figure. For this purpose, Croc first murdered Squid, an uprising crimelord and then he attempted to seize control of the Tobacconists' Club. His criminal activities made him a target of Gotham's vigilante Batman.

Croc's rise to the top of Gotham's underworld didn't go unnoticed and he made quick enemies of already established criminals. Croc was soon approached by Joker, who arranged a plan for Croc to eliminate Batman, but the madman's plan would also involve a double-cross, where Croc would be eliminated as well. Joker's plan failed and in the last confrontation with Batman, Croc was defeated and his reign of terror was over.

Some time later, notorious sociopath Ra's al Ghul engineered a massive breakout of Arkham Asylum, freeing all of the patients, including Killer Croc. In exchange for their freedom, the prisoners agreed to help Ra's with a scheme to confound the Batman. Croc's role in the plan was to break into Wayne Manor and abduct Bruce Wayne's butler Alfred Pennyworth. 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. Batman soon arrived to rescue the hostages and fought with Croc once again. As time was of the essence, Batman wasted little of it fighting Croc, and quickly subdued him with a gas pellet from his utility belt. Afterwards, Killer Croc was returned to Arkham Asylum.

Like many do, Croc eventually escaped from Arkham and began running criminal operations again. After robbing a shopping store, Croc discovered a secret stairwell that led into an old unfinished subterranean highway. The tunnel had since become a shelter for many of Gotham's homeless. Croc became friends with the homeless people and attempted to make a new life for himself. Croc's newfound lifestyle was short-lived however. Batman investigated the store robbery, and the trail led him right to Killer Croc's shelter. The two began fighting one another, but at midnight, the city flushed the tunnels with water from the river, and Croc was washed away. His friends believed that he had died in the flood.

Knightfall

Croc survived however, and six months later had taken to living out of the Gotham City alleyways. He was tormented by visions of his past, calling to mind hurtful incidents where his peers would routinely comment about his physical features. In combination with his natural, instinctive rage, Croc's emotional state erupted into a wave of violence and he began going berserk throughout the city streets. News crews captured his latest rampage, as he began terrorizing the district known as Eden Park. An aspiring foreign crime lord known as Bane witnessed Croc's rampage, and determined that defeating him would be a stepping stone on his personal path towards destroying Batman. Before Bane could catch up with him though, Croc found himself facing neophyte vigilante Jean-Paul Valley, as well Batman's young sidekick Robin. Bane interrupted the fight and demonstrated his raw power by breaking both of Croc's arms.

Croc was sent back to Arkham Asylum, where he spent a very short period of time because a few weeks later, Bane attacked Arkham and unleashed all the inmates including Croc. Wandering through the sewers of Gotham, the only thought in Croc's mind was getting revenge against Bane. His opportunity came when he discovered Bane had captured Robin and taken him to the sewers. Croc fought Bane and destroyed the venom pumping machine, but Bane broke his arm again. They were dragged by the water to the river outside and Croc was left unconscious after the fight.

Prodigal

Croc soon healed and returned to Gotham in an effort to re-establish himself in the criminal underworld. He went on a brutal murder spree that claimed the lives of several members of the Paretti crime family operating out of Gotham's waterfront district. At this point in time, Bruce Wayne had relinquished the role of Batman to his first ward Dick Grayson. As the new Batman, Dick and Robin fought with Croc at a warehouse. Surviving members of the Paretti gang were present and opened fire on Croc severely wounding him. Croc survived once again however and evaded capture.

Years later, Killer Croc was summoned by some strange paranormal force to break out of Arkham Asylum and make his way to the Louisiana swamps. Batman followed him there only to find that the mysterious force was actually the Swamp Thing, who offered Croc a place in the swampland where he could finally give in to his animal side and live free from human persecution. There he stayed, and Batman returned to Gotham City.

Hush Virus and Mutation 

On a grand scheme to take Batman down, Hush implanted a virus in Croc that caused his body to devolve into a more primal and reptilian state. In this state, Croc was told to kidnap a rich kid and to claim the ransom to treat his condition. However, Hush was using him for other purposes and Croc was captured by Batman. 

Croc was then taken to Arkham Asylum, where Batman questioned him about the money, but Croc managed to escape and Batman allowed it in order to follow the monster. Croc went to see Catwoman, who took the money after he was captured. Batman stopped him from hurting her and when Croc was revealing that the money was to cure him, Amanda Waller and the F.B.I captured Croc and took him into custody.

Croc is then treated by the police and a doctor named Maria Belleza and shortly after, Croc is cured and returned to his "normal" appearance.

During the great gang war of Gotham, Croc was present at the massive criminal meeting at Robinson Park and he was one of the first criminals to attack Batman, biting his cowl and destroying the radio intercom. Croc was preventing Batman from reaching Black Mask until Robin arrived and defeated Croc using his staff. Afterwards, Croc joined Scarecrow and they followed Black Mask to the North End of Gotham.

However, Black Mask kidnapped Croc and with the help form Mad Hatter, they implanted a mind-controlling chip in Croc's brain allowing Black Mask to force Croc to do his biddings. A few days later and during one of Black Mask's bank heists, Croc removed the chip from his brain and slaughtered Black Mask's henchmen. After this, he went looking for Mad Hatter and was about to devour the man when he was stopped by Batman, who explained that Croc had a brain infection that could kill him and that the virus that caused him to mutate so severely has reactivated and his mutation would worsen with time. Batman dosed Croc with an antibiotic to save his life and Croc escaped from the place, with a desire for revenge against Black Mask.

Croc looked for Maria Belleza again and on his way to her he slaughtered more members of the False Face Society. Doctor Maria Belleza was a scientist whose knowledge about Croc's disease allowed her to get closer to Croc than any human has ever before. However, Maria's antidote was short lived and the mutation started again. After long tests, Maria concluded that there was no cure and Croc, losing control over himself, devoured the doctor, following his animal instincts but regretting the action with his human conscience. With vengeance in mind, Croc went looking for who was responsible for his mutation.

Croc was later discovered feeding off the remains of the villain Orca. He was apprehended once again and taken back to Arkham Asylum.

One Year Later

While being transferred from one prison cell to another, Croc wrestled free from his handlers and attacked visiting reporter Jimmy Olsen. Olsen spontaneously generated super-powers and was able to escape unharmed. Killer Croc soon escaped confinement however, and was one of many super-powered villains led by Deathstroke who crashed the wedding of Green Arrow and Black Canary. Fortunately, the wedding party was made up of members of the Justice League, the Justice Society, the Outsiders and the Teen Titans. By the end of the fight, most of the villains, including Croc, were apprehended. The administrators of Checkmate later decided that Croc was too dangerous for them to safely contain him. He, along with many others, were exiled from the Earth via Boom Tubeand taken to the "Salvation" World.

Upon returning to Earth, Croc along with other supervillains like Mr. Freeze, fought to regain control of the city by taking out Intergang. However, Croc was eventually captured and taken to Arkham Asylum.

After the Black Glove's failed plan to destroy Batman, all the inmates from Arkham Asylum were transferred to Blackgate until Arkham was completely decontaminated. On their way back to Arkham, the vehicles that transported the inmates were assaulted by a new Black Mask, who freed the inmates, blew the asylum in front of all of them and forced them to join his army. Croc was among the inmates who joined Black Mask's group and under his instructions, he worked together with Poison Iyv, located the Batmobile and attacked Damian Wayne, who was rescued by the timely arrival of Nightwing. Afterwards, Croc, Ivy and Firefly attacked and destroyed several factions of Penguin's gang, following Black Mask's instructions.