Superman can also be an opponent in some 'death battle batman fanfiction'. It's an interesting match - up as it pits Batman's brains and preparation against Superman's superhuman strength. Writers often explore how Batman could potentially defeat someone so much more powerful.
Another common opponent is Bane. In these fanfictions, the battles are intense as Bane is physically very strong. Batman has to find ways to overcome Bane's brute force, usually by using his environment and his own knowledge of Bane's weaknesses.
Ra's al Ghul is another common foe. His immortality and vast resources can create complex and engaging death battle situations against Batman in fan - made stories.
Venom is a very common opponent. Given their history in the official comics, it's natural for fanfiction to explore their battles further, especially in a death - battle scenario where the stakes are even higher. Their symbiotic relationship adds an extra layer of complexity to the fight.
One likely opponent is Luke Castellan. Since they have a complex relationship in the original series, it would be a very emotional and intense battle in fanfiction. Luke has his own set of skills and powers, and his motives would make the battle even more interesting.
Another common opponent could be other demigods from different cabins. For instance, a child of Ares who might have a more aggressive and straightforward fighting style compared to Percy. This would create an interesting dynamic as they have different powers and personalities but are still on the same side in the general scheme of things.
One interesting 'death battle batman fanfiction' could be where Batman faces off against an otherworldly demon. In this story, Batman uses his wits and a new set of high - tech gadgets he's developed. He has to outsmart the demon's magical abilities with his strategic thinking.
Another could be Kaguya Otsutsuki. However, in the fanfiction, she may return in a more powerful form. Maybe she has found a way to break free from the seals completely and has amassed even more power from other dimensions. Naruto, being abnormally strong, would still have a tough time fighting her as she is one of the most powerful characters in the Naruto lore.
Well, in some fanfictions, the battle might start as a misunderstanding. Spiderman could be in Gotham chasing a bad guy who has a connection to New York and Batman mistakes him for a new threat. In this case, Spiderman would try to explain himself but Batman, being the brooding detective, might not listen. Then there are scenarios where the battle takes place in a neutral location like an abandoned warehouse. Here, both of them have to rely on their skills and resources. Spiderman would use his webs to create obstacles and Batman would use his gadgets to break through them. Also, there could be a scenario where they team up against a greater threat first and then due to a clash of egos, they end up fighting each other.
Often, it's powerful villains like Orochimaru who make a comeback in fanfiction. Naruto has to use his growth and new abilities to defeat him once and for all.
One common opponent could be Salem. Since they are major antagonists in the RWBY universe, fanfiction often pits them against each other in epic battles.
Monsters from Greek mythology are also very common. Giants, like the ones Percy faced in the original series, are frequently used. They are powerful and require Percy to use his water - based powers in creative ways to take them down. It's a classic type of fight that fans love to read about.