Perhaps Killer Croc's unique abilities could be related to a new type of jutsu in the Naruto universe. For example, his tough skin could be like a natural armor jutsu that Naruto characters are interested in studying. Or he could be a part of a secret experiment in the Naruto world that gives him his powers, and Naruto has to figure out what's going on. There could also be a story where Killer Croc is from a parallel universe and is brought to the Naruto world by an evil force, and Naruto has to send him back while also dealing with the chaos he causes.
One plot idea could be that Killer Croc somehow ends up in the Naruto world and has to learn chakra control. Maybe he starts as a villain but then teams up with Naruto's group against a greater threat.
One idea could be that Naruto is transported to a different universe where he somehow gets cursed and starts to transform into Killer Croc. As he struggles with this new form, he has to find a way to reverse it while also dealing with the reactions of the people in this new world.
One plot idea could be that the OC is a scientist who is studying Killer Croc. They start off with a professional relationship but gradually develop a strange bond. Maybe the OC discovers a way to temporarily suppress Killer Croc's more violent tendencies, and this leads to them spending more time together. As they interact, the OC begins to see the humanity in Killer Croc that others overlook.
One plot idea could be Killer Croc forming an unlikely alliance with a small group of outcasts in the city. They initially fear him because of his appearance but come to realize he has a good heart. Another could be Killer Croc's struggle to adapt to a new environment outside of his usual sewers, perhaps in a more rural area where he has to deal with different challenges. A third idea is a story where Killer Croc discovers a hidden power within himself during a fight with a powerful enemy and has to learn to control it.
One possible plotline could be that the Killer Croc is accidentally transported to the Forbidden Forest in Hogwarts. The Hogwarts professors and students then have to figure out how to deal with this dangerous and unfamiliar creature. Another plotline might involve a dark wizard using the Killer Croc as a weapon to attack Hogwarts, and the students have to find a way to stop it.
He would likely have a very different physical appearance. With Killer Croc's scaly skin and large build, Naruto would lose his normal human - like form. This would probably shock his friends at first. For example, Sasuke might not recognize him right away.
Well, perhaps the bloodline could grant superhuman strength like Killer Croc has in the DC universe, which in the Naruto world might translate to being able to break through earth - style jutsu defenses more easily. Also, it could give the ability to swim at great speeds and hold one's breath for long periods, useful for underwater missions or battles near water sources in the Naruto world.
In Batman Killer Croc fanfiction, there could be an unusual alliance where Killer Croc teams up with Batman against a common enemy. This enemy could be a new supervillain who has a plan to take over Gotham's underworld and Croc's territory. Croc might see the benefit of working with Batman temporarily to protect his own interests.
To create a believable character arc for Killer Croc, start with his backstory. Show his early life and how he became the way he is. Maybe he was once an ordinary person who was experimented on. Then, as the story progresses, have him face challenges that force him to change. For example, if he meets a group that accepts him, he might start to become more trusting. By the end, he could be on his way to becoming a more heroic figure, or at least less of a feared outcast.
Well, another place to find 'Naruto Killer Croc fanfiction' could be Archive of Our Own. Some authors might explore unique storylines like Killer Croc being a summoned creature in the Naruto universe or having Naruto characters interact with a version of Killer Croc from another dimension. It's all about the creative interpretations that fans come up with.
The Killer Croc's origin story involves him having a genetic condition that made him more reptilian over time. He was often bullied due to his appearance, which led him to a life of crime. His transformation made him stronger and more savage, and he became a feared criminal in Gotham City.