Who could be the main villain in a 'Trunks x Justice League' fanfic?

It could be an evil version of Victor himself. Maybe in an alternate timeline or due to some dark magic, Victor turns bad. His knowledge of the Justice League and his own powers would make him a formidable foe. He could be trying to take over the world or exact revenge on the League for something that happened to him in the past.

Darkseid as a vampire - like being. He could come to Earth and start turning people into his vampire minions. His already formidable powers combined with vampiric abilities would make him a terrifying foe for the Justice League.

Brainiac would be a great choice. He has advanced technology that could be a huge challenge for the OC gamer. The OC might have to use their gaming knowledge to outwit Brainiac's complex systems and plans. For instance, if Brainiac tries to assimilate the world's knowledge, the OC could use their strategic gaming skills to disrupt his data - collecting devices.

Darkseid would be a great main villain. He's already a powerful and well - known foe in the DC universe. He could be the one who starts collecting the Infinity Stones - like items to gain ultimate power and rule over all universes. His army could also be involved, making it a large - scale war for the Justice League.

It could be Eggman. He might team up with some of the Justice League's villains, like Lex Luthor. Eggman could bring his mechanical creations and knowledge of chaos emeralds, while Luthor provides his strategic mind and resources. Together, they could pose a huge threat to both Sonic and the Justice League.

The Highbreed could also serve as the main villain. They are a powerful and xenophobic race in the Ben 10 universe. In a crossover, they might view the Justice League's world as a place to expand their territory. They could use their advanced technology and large numbers to attack. Ben would have to convince the Justice League that the Highbreed are a serious threat and together they would need to find a way to stop the Highbreed's invasion, perhaps by using Ben's alien forms like Upgrade to hack into their technology and the Justice League's strategic planning.

Voldemort could be a main villain. Imagine him getting his hands on some of the Justice League's technology and using it to enhance his dark magic. He could become even more powerful and pose a threat not just to the wizarding world but also to the world the Justice League protects.

A good main villain could be Brother Eye. It's a powerful and menacing artificial intelligence. In a crossover, it could have evolved in the future to be even more dangerous. It could pose a threat to both the future world of Batman Beyond and the past era of the Justice League, forcing them to team up to take it down.

Perhaps Trunks is initially mistaken for a threat by the Justice League. But as they learn more about him and his mission to protect his own timeline, they start to work together. For example, Trunks could share his knowledge of advanced Saiyan fighting techniques with Batman, who then uses this knowledge to develop new strategies for the team. Meanwhile, Wonder Woman could teach Trunks about the different cultures and values in the Justice League's world.

Ink could be a great main antagonist. He has the power to manipulate shadows and could use this ability to create chaos in Gotham and beyond. He might target the Justice League and Batman Beyond because they represent order and he wants to spread his own brand of darkness.