Risty is another candidate. She has a mysterious charm and her thieving skills could come in handy. In a crossover with a high - seas pirate story, she could be the one to steal the map to a hidden treasure. But at the same time, she might have to deal with the moral code of the pirates she teams up with, which could lead to some interesting character development.
I think Leina would be a great choice. She has a strong sense of justice and is always looking to improve herself. In a crossover, she could be the one to bridge the gap between different groups or worlds. For instance, if crossed over with a space - faring civilization, she might be the first to try and understand their technology and culture, while also showing them the values of her own world.
Ruby would be really interesting. Her innocent and positive attitude would contrast greatly with the dark and desolate Fallout world. She'd be like a ray of hope in the wasteland. Her scythe - fighting skills would also be unique and useful against the various threats in Fallout. She might try to befriend some of the mutants or ghouls, seeing them not as just monsters but as living beings who need help.
Sinister characters like Adam Taurus from RWBY could also be interesting in a Bloodborne crossover. His already dark and violent nature could be enhanced in the Bloodborne setting. He could form alliances with some of the more sinister forces in Bloodborne, or perhaps he becomes a sort of anti - hero, fighting against the greater evils in the Bloodborne world while still being a morally ambiguous figure.
Luna Lovegood would be an unexpected but fascinating choice. Her unique perspective and belief in all kinds of magical creatures could make her very open - minded about the vampires and werewolves in the Twilight world. She might see them as just another type of magical being and try to find common ground, which could lead to some really interesting interactions and storylines.
Definitely Alex Mercer. His powers are so unique compared to the Justice League members. He can shapeshift into anyone, has superhuman strength, and can regenerate from almost any injury. This would create a lot of interesting interactions with the League. For example, he could transform into Superman to test the limits of his own power against the real Superman, which would lead to a really cool showdown.
Scott would be really interesting. His role as an alpha werewolf could lead to some great storylines in the Fate universe. He could be seen as a powerful being there, and his sense of leadership and loyalty would be put to the test. He might have to make difficult decisions about which side to take in Fate's complex power struggles.
Raphael could be really interesting. In the 2003 version, he is hot - tempered and tough. In the 2012 version, he also has a strong personality. Seeing how he reacts to his counterpart and how they might either clash or bond could be a great focus. Maybe they have a friendly rivalry as they compare their fighting skills.
Ross could be really interesting. Since he's an archaeologist, in a crossover with a show like 'Indiana Jones' (in a fanfiction sense), he could go on an adventure with Indiana Jones. Ross would bring his academic knowledge while Indy would have the practical experience. Their interactions would be filled with Ross trying to over - analyze everything and Indy just wanting to get the job done.
Chiaki Nanami could be an excellent choice. She is the Ultimate Gamer, so if you cross her with a digital or virtual world, there are so many possibilities. She could use her gaming skills to navigate through a new digital realm, like a Matrix - like world. Her calm and intelligent nature would also make her a great character to lead the group in a crossover situation. She could figure out the rules of the new world quickly and help the others adapt.
Sora would be really interesting. His naivete and pure heart could be a great contrast to the dark and gritty world of Blade. He would probably approach the vampire - fighting situation with his usual optimism and might even try to find a way to redeem some of the vampires, thinking they are like the lost souls he has saved in the Kingdom Hearts worlds.
Nico di Angelo would be an interesting choice. His dark and brooding nature along with his powers over the dead would be a contrast to the more light - hearted aspects of the Harry Potter world in some ways. He could introduce the wizards to the concept of the Underworld and the spirits. And his ability to shadow - travel could be used in some really creative ways, like getting the group in and out of dangerous situations quickly, whether it's in Hogwarts or in the magical areas related to Greek mythology.