Inklings from Splatoon could also be fun to include. The Inklings' ink - based attacks and their unique culture could add a new dimension to the story. They could team up with Joe to stop an enemy that is trying to cover both their worlds in some sort of dark, gooey substance. Joe would have to figure out how to work with the Inklings' different combat style.
How about a crossover with Sonic the Hedgehog? Picture this: Sonic is running through a strange new zone and accidentally enters Joe's world. They join forces to stop Dr. Eggman who has somehow teamed up with one of Joe's enemies. Sonic's speed and Joe's Viewtiful powers would create a really fast - paced and exciting story.
Joe would probably be very confused at first in the School DxD world. He's used to his own kind of battles, and suddenly being in a world full of devils, angels, and other mythical creatures would be a shock. He might be very cautious and try to figure out who the good guys and bad guys are. The devils in School DxD might be intrigued by Joe's powers and either try to recruit him or study him. The angels, on the other hand, might be more suspicious and see him as a potential threat at first.
Cobra Commander could also be a great addition. His evil plans and his forces could provide the main conflict for Snake Eyes in the crossover. And if we want to expand the scope, characters from other military - themed franchises could be included. For instance, characters from 'The A - Team' could make for an interesting crossover. They have different fighting styles and personalities that could clash or mesh well with Snake Eyes. Imagine Face and Hannibal devising plans while Snake Eyes executes them with his ninja stealth.
A great plot could involve a powerful enemy that has the ability to drain the 'viewtiful' energy from Joe. Tsukune and his friends notice the weakened Joe and decide to help. They all train together, combining their different powers and skills. The story could then build up to an epic showdown where they all have to use their combined strength to defeat the enemy and Joe regains his full 'viewtiful' power.
The interaction between Viewtiful Joe and Moka would be really interesting. Moka's vampire powers and Joe's 'viewtiful' abilities could create some really cool fight scenes. Also, their different personalities - Moka's shy - vampiric duality and Joe's confident heroism - would make for some great dialogue and character development moments.
In a Dorohedoro crossover with 'One Punch Man', Saitama would be an interesting addition. His overpowered nature would contrast with the often - more - gritty and complex power levels in Dorohedoro. Another good character could be Guts from 'Berserk'. His dark and brooding personality would fit well in Dorohedoro's gloomy atmosphere. Also, Edward Elric from 'Fullmetal Alchemist' could bring his knowledge of alchemy and his quest for truth to the Dorohedoro world.
In vegito crossover fanfiction, characters like Jiren would be great. His strength and stoic nature would make for some intense interactions with Vegito. Also, Android 18 could be included. She has her own unique set of powers and a strong will. Her presence could add some interesting dynamics, especially if she has to team up with Vegito against a common enemy. And don't forget Frieza. His evil nature and thirst for power always make for an exciting addition to any Dragon Ball - related story.
Kenny McCormick (Mysterion) could cross paths with Batman. Batman's detective skills and high - tech gadgets would make for an interesting dynamic with Mysterion's more 'underground' superhero style. They could work together to solve a mystery that spans Gotham City and South Park.
For a crossover with Doctor Who, the Doctor could be an interesting addition. He could bring his time - traveling abilities and vast knowledge to the Shadow World. And from the Shadowhunter side, Jace Wayland would be a good character to include. His charm and combat skills would make for some interesting dynamics with characters from other universes.
For a crossover with a post - apocalyptic world, characters like Mad Max could be involved. He might see the homunculi as either allies or threats in the harsh new world. In a crossover with a cyberpunk world, characters like Neo from 'The Matrix' could be interesting. The homunculi could be part of the complex digital and physical world that Neo navigates, and he could help them understand the true nature of their existence in this new, high - tech world.