Who could be the main antagonists in 'rise of the dragon child fanfiction'?

One potential main antagonist could be Orochimaru. Since he is always interested in immortality and forbidden jutsu, he would surely be intrigued by Naruto's condition. He might try to capture Naruto to conduct experiments on him to gain the secret of his immortality for himself.

Perhaps an ancient evil spirit that has a connection to death itself. This spirit sees Naruto as a threat because of his emerging powers related to death and tries to eliminate him before he becomes too powerful. The spirit could be using other villains as pawns to do its bidding.

Maybe some evil wizards or dark creatures. They could sense the power of the growing dragon and want to either control it for their own evil purposes or kill it to prevent it from becoming a threat to their plans. They would see Bilbo as an obstacle in their way.

There could be an old dragon that has been in exile for a long time. This dragon might see Hiccup as a threat to its plan of taking over the dragon kingdom. So it tries to stop Hiccup from fully becoming a dragon or tries to use his new form for its own evil purposes.

Blackbeard could also be a main antagonist. He has his own ambitions for power and the One Piece. With Luffy getting stronger under Dragon's training, Blackbeard would view Luffy as a direct competitor. Their paths are bound to cross, and Blackbeard would not want Luffy to achieve his goals before he does.

The Titans could be great antagonists. They might see Percy as a threat to their plans of overthrowing the gods again. Since Percy has chaos powers, they could fear that he could disrupt their carefully laid - out schemes. Another possibility is some of the more traditional enemies of the demigods, like the monsters. They might be drawn to Percy's chaotic energy and try to either consume it or destroy him to prevent him from becoming too powerful.

Maybe it's a group of intergalactic criminals who are after the power that Peter Parker has as a 'child of the universe'. They could be stealing artifacts from different planets to gain more power and they see Peter as the ultimate source of power that they need to complete their collection.

It could be other villains who are jealous of Izuku's powerful dragon quirk. They might see his quirk as a threat to their own plans for domination or chaos.

It could be a group of rogue demigods who want to use the Dragon King's power for their own evil purposes. They might be jealous of Percy's status and see the Dragon King as a means to gain more power and control in the mythical world.

It could be an organization of rogue ninja who have also somehow gained similar powers but use them for destruction. They see Naruto as a threat to their plans of taking over the ninja world with their newfound powers. They constantly try to undermine Naruto and steal his unique Crystal Dragon Slayer techniques.