If it's a crossover with Teen Wolf, Stiles would be a great character to include. His quick thinking and sarcastic nature would contrast well with the more serious Shadowhunters. He could also provide some unique insights into solving problems, especially when it comes to the werewolf aspects of the Teen Wolf world that the Shadowhunters might not be as familiar with.
In a crossover with the X - Men, Wolverine would be an interesting addition. His tough and no - nonsense attitude, along with his combat skills and healing factor, would make him a formidable ally or a challenging opponent for the Shadowhunters. His past and his search for identity could also tie in well with the themes of self - discovery that are often present in Shadowhunters stories.
If we consider a crossover with the Lord of the Rings universe, Aragorn could be a good fit. He's a noble leader and a skilled warrior. His presence could force the Boys to reevaluate their ideas about power and leadership, and he could also be a strong ally against any corrupted power - hungry characters from the Boys' world.
The Terraria Guide could be a great character to include. He has a lot of knowledge about the Terraria world, so in a crossover, he could be the one trying to figure out the new world they're in. For example, if it's a crossover with Terraria and Hollow Knight, he could study the strange bugs and lore of the Hollow Knight world.
Slenderman would be an obvious choice. He has a connection to Jeff in the horror lore. Their interaction could range from being allies in a shared goal, like spreading fear, to being enemies as they compete for territory or influence in the horror world.
In a crossover with Halo, Master Chief would be a great addition. His combat skills and strategic thinking could interact well with the large - scale battles in Supreme Commander. He could lead the UNSC forces against the massive armies in the Supreme Commander world.
In a crossover with the Avengers, characters like Iron Man and Captain America would be great. Iron Man could be intrigued by the technology of the lightsabers and try to replicate it. Captain America, on the other hand, could admire the Jedi's code of honor and fight alongside them against a common enemy, perhaps Thanos who is also after some powerful Force - like artifacts.
One character that would be interesting to include is Batman. His combat skills, detective abilities, and vast array of gadgets would make him a formidable ally against the zombies. Then there's Katniss Everdeen from 'The Hunger Games'. Her archery skills and survival instincts would be very handy. Additionally, Doctor Strange could be a great addition. His magic could be used to create barriers against the zombies or to teleport the characters out of dangerous situations in the 'highschool of the dead' setting.
Well, if you cross it with the Star Wars universe, Darth Vader could be an interesting addition. His dark power and combat skills would be a great contrast to the characters from Into the Badlands. It would be fascinating to see how they interact and whether they could form an alliance or end up as enemies.
Definitely Endou Mamoru from Inazuma Eleven. His positive attitude and never - give - up spirit can be a great influence in any crossover. If it's a crossover with a superhero story, Superman could be included. The contrast between Endou's down - to - earth determination and Superman's superhuman powers would be fascinating. Also, Naruto from the Naruto series. His growth and his ability to inspire others would mesh well with the Inazuma Eleven characters.
Definitely Jak and Daxter. Jak has his own set of combat skills and a dark eco - powered form that could add an interesting dynamic. Daxter, being his sidekick, provides some comical relief with his sassy remarks. Sly Cooper would also be a great addition. His stealth and acrobatic skills are top - notch, and his interactions with Ratchet and Clank could be really entertaining. Bentley, Sly's tech - savvy friend, could also collaborate with Ratchet on some cool gadget - related things.
You could include characters from other crime - themed games like Tommy Vercetti from Grand Theft Auto: Vice City. His experience in the crime world could create some interesting dynamics with the Mafia 3 characters. They could either be rivals or form an uneasy alliance.