One idea could be a battle in an alternate dimension where the laws of physics are different. This would force both Superman and Omni - Man to adapt their fighting styles. Another could be a scenario where they are forced to team up against a greater threat first, before their own conflict resurfaces.
It's hard to say for sure. Omni - Man has incredible strength and combat experience. However, Superman has near - invulnerability and his powers are powered by the sun. If the fight takes place on Earth, Superman has the home - field advantage with the sun constantly recharging him. But if it's a long - drawn - out battle, Omni - Man's tenacity could also be a factor. In my opinion, Superman's powers are more diverse and powerful, so he would likely come out on top.
One idea could be that Batman and Superman are forced to team up against a common enemy from another dimension. This enemy has the power to manipulate the minds of the citizens of Metropolis and Gotham, making them turn on their heroes. Batman uses his detective skills to find the source of the mind control, while Superman has to hold off the hordes of brainwashed civilians.
One idea could be an OC who has the power to nullify Superman's powers temporarily, making the fight more evenly matched against Batman. This OC could be a scientist who has developed a special device after years of studying Kryptonian physiology.
One idea could be that Naruto is somehow transported to the DC universe. He teams up with Batman against Superman who has been mind - controlled. Naruto uses his Rasengan and shadow clone jutsu to help Batman outwit Superman's super strength. Another plot could involve a tournament where Naruto, Batman, and Superman all compete, with Naruto's ninja skills being a wild card in the mix.
One idea could be a story where Batman and Superman have to team up against a common enemy before their big fight actually happens. Maybe a powerful alien threat that forces them to realize they need each other's skills.
Maybe there's a plot where a powerful alien force arrives on Earth and starts causing chaos. Superman is having a hard time dealing with it alone as the aliens have some new form of kryptonite - like energy. Catwoman, with her stealth and street - smart skills, discovers a way to neutralize the kryptonite - like effect, and they join forces to save the day.
A really interesting idea in Bardock and Omni - Man fanfiction could be a story where they are both forced to fight in an inter - galactic gladiator arena. This would force them to work together despite their differences. Bardock's warrior spirit and Omni - Man's strategic mind would make for an exciting combination as they try to survive and outwit their opponents.
One plot idea could be that Superman and Supergirl team up to face a new, powerful alien threat that is immune to their normal powers. They have to rely on their wits and discover new abilities within themselves. Another could be a story where they travel to an alternate dimension where their roles are reversed. For example, Supergirl is the more well - known hero in that world and Superman has to learn from her.
One idea could be that Superman and Invincible have to team up to stop an alien invasion that threatens both their worlds. The two heroes could initially clash due to their different methods but then learn from each other.
One idea could be that an alternate - universe version of Superman comes to their world. This could lead to a power struggle as both Supermen have different ideas on how to protect the city. Another plot could involve Lois getting superpowers temporarily and having to learn how to use them while also dealing with her regular reporting job.