The alchemists' ability to transmute matter could be combined with the Mushishi's ability to interact with the Mushi. For instance, an alchemist could transmute a substance to create a container or tool that can better detect or contain the Mushi. The Mushishi, in turn, could use their understanding of the Mushi to guide the alchemist in what kind of transmutation would be most effective. For example, if a particular Mushi is attracted to a certain type of metal, the Mushishi could inform the alchemist, who could then transmute that metal into a trap.
One potential storyline could be that the alchemists in Full Metal Alchemist somehow stumble upon the world of Mushishi. Maybe they are on a quest for a rare ingredient or to study a unique form of alchemy. In this new world, they encounter the Mushishi, who have their own set of rules and powers regarding the Mushi. The two groups could initially be at odds, with the alchemists' scientific approach clashing with the more spiritual and natural approach of the Mushishi. But as the story progresses, they might find common ground in their pursuit of understanding the mysteries of their respective worlds.
Well, consider Wendy's healing magic. In a crossover, she could use her magic to heal the wounds caused by alchemical experiments gone wrong or battles in the Fullmetal Alchemist world. In return, the alchemists could teach her about the properties of different herbs and substances that could enhance her healing magic. Gajeel's iron dragon slayer magic could interact with the metal - based alchemy. He could use his magic to shape and manipulate metal in ways that the alchemists find fascinating. And then there's Mirajane's transformation magic. She could transform into forms that are better suited to deal with the alchemical threats in the Fullmetal Alchemist world, while the alchemists could help her understand the physical and chemical changes that occur during her transformations.
Let's start with Naruto's ability to control the Nine - Tails' chakra. In a crossover, this could be related to the power of the Philosopher's Stone in Fullmetal Alchemist. Maybe the Nine - Tails' chakra has some alchemical properties that can be harnessed. Edward could study this and find a way to use it in his alchemy. On the other hand, the alchemical transmutation circles could be used as a form of jutsu in Naruto. The ninja could draw these circles on the ground or on their bodies to activate different powers. For example, Rock Lee, who doesn't have natural chakra control, could use alchemical transmutation to enhance his physical abilities. He could transmute his muscles to be stronger or more elastic. And for the Homunculi, they could use their immortality to outlast the ninja in long - term battles and learn their techniques over time.
Well, think about it. A Pegasus pony can fly, so it could team up with a Flying - type Pokemon like Pidgeot. The pony could carry the Pokemon to higher altitudes for a better vantage point in battle or for scouting. In terms of other abilities, the MLP characters' friendship - based magic might have an impact on the Pokemon. Maybe it could make the Pokemon more loyal or boost their morale, which in turn would make them fight better. For example, Fluttershy's kindness might make a Pokemon less likely to be intimidated by an opponent.
The demigods have a variety of powers. Annabeth's strategic mind could be combined with Alice's ability to see the future. They could plan out battles or ways to avoid danger. If a demigod like Jason with his lightning powers teams up with the vampires, they could use the lightning to create distractions or even as a weapon against common enemies. The vampires' super strength and speed could also be useful in getting the demigods out of tight spots quickly.
Harry's ability to use magic like the Patronus charm could be combined with Naruto's Rasengan. Maybe Naruto could infuse his chakra into Harry's magic, creating a more powerful and unique attack. Hermione's knowledge of spells could be used to enhance the ninjas' strategies. For example, she could create a spell that would make the ninjas' clones more durable, similar to how they are in the Naruto world but with a magical twist.
Kaneki's kagune could be used in combination with Shinichi's parasite - enhanced physical abilities. For example, Kaneki could use his kagune to create a distraction while Shinichi uses his speed and strength to attack the enemy. Or they could work together in a more direct way, with Shinichi using his parasite - hand to hold an enemy in place while Kaneki delivers a powerful kagune strike.
The telepathic abilities in Young Justice, like Miss Martian's, could be very useful for the Totally Spies when it comes to getting information from enemies. In return, the spies' disguise and infiltration skills could help the Young Justice characters get into places they normally couldn't. They could work together in a mission where the spies pose as normal people and the Young Justice characters are there as backup, using their powers secretly when needed.
Well, Spider - Man's web - slinging ability could be used in really creative ways when combined with the powers of the Young Justice characters. For example, if he teams up with Superboy, Superboy could use his strength to throw Spider - Man into the air, and then Spider - Man could use his webs to swing around and attack enemies from different angles. It would be like a super - powered aerial assault.
Well, Naruto's shadow clone jutsu could be really useful in a fight alongside Saitama. The clones could distract enemies while Saitama gets in a powerful punch. And Saitama's super strength could help Naruto in situations where brute force is needed more than ninjutsu. For example, if they had to break through a really thick and magically reinforced wall.