In this fanfic, there could be a scenario where Batman is exposed to Kryptonian technology that gives him some Kryptonian - like abilities temporarily. A Kryptonian comes to Earth to study this anomaly. They start off as adversaries but as they learn more about each other, they find that they can work together to protect Earth from a greater threat that only their combined skills can defeat.
Maybe the Kryptonian werewolf is a protector in a different way. Instead of being a traditional hero like Superman, the werewolf form gives them unique abilities to protect the city at night or in certain dangerous situations. They could form an unlikely alliance with other characters in Metropolis, like a detective who is trying to solve a series of crimes that seem to be related to the werewolf's presence.
Another interesting concept is a Kryptonian OC who is part of a secret society on Earth. They keep their identity hidden from the world, but within this society, they use their powers to maintain order and justice in a more shadowy way. They might have to deal with internal power struggles within the society as well as external threats to their secrecy.
A human male detective could be investigating strange occurrences in the city when he encounters a Kryptonian female superhero. They start working together to solve crimes and protect the city. Along the way, their relationship blossoms as they discover they have more in common than they thought, like their strong sense of justice.
It can be a relationship of mutual respect. The Kryptonian respects Batman's intelligence and determination despite being a mere human. Batman respects the Kryptonian's power and their sense of justice. They might have different approaches to solving problems, but they recognize the value in each other's methods. For instance, when facing a powerful villain, Batman would come up with a strategic plan while the Kryptonian uses their powers to execute it.
One idea could be that Naruto is somehow given Kryptonian powers. He might start using his newfound super strength and flight in his battles in the ninja world. For example, he could use his super speed to outmaneuver opponents more easily during a fight with Akatsuki members.
Well, a plot could be that the reborn character discovers a hidden power within Kryptonian abilities that no one else knew about. This could put them in a position where they are both feared and revered. Also, they could form an unlikely alliance with a group of Kryptonians who were considered outcasts. Together, they try to bring about a new era on Krypton. Another interesting plot would be the character being sent on a mission to a different planet. Since they are reborn as a Kryptonian, they have unique skills for this mission and face various challenges during it.
A plot idea could be that Poison Ivy creates a new type of plant - based virus in Arkham that only affects humans who are harming the environment. Batman has to find a way to stop the virus from spreading while also dealing with Ivy's strong beliefs. Another idea is that Ivy discovers a rare plant in Arkham that she believes can save the planet, but it's in a highly guarded and dangerous area. Batman and Ivy might have to work together to retrieve it.
One idea could be exploring Bruce Wayne's early training in more detail. Show his struggles and how he overcame them. For example, his first encounters with Ra's al Ghul's League of Shadows could be more in - depth, with new challenges and characters added.
One idea could be that the Witchblade somehow ends up in Gotham City. Batman initially suspects it to be a new weapon in the hands of some villain. But as he investigates, he discovers the unique power and origin of the Witchblade. Maybe the Witchblade chooses Batman as its wielder for a short time to fight against a powerful supernatural threat that Gotham has never faced before.
A plot could involve Batman investigating a mystery that has ties to Themiscyra. For example, some ancient artifacts from Themiscyra are showing up in Gotham's black market. As he delves deeper, he discovers a connection to a long - lost Amazonian prophecy. Or perhaps there's a character from Themiscyra who has come to Gotham seeking Batman's help to save her homeland from an internal power struggle.