The power systems interaction could be really complex. Take Naruto's Sage Mode. In a crossover, it could be seen as a way to access a different level of power similar to how Servants access their Noble Phantasms. The natural energy in Sage Mode could be equated to a special type of mana. And for the Fate side, a Servant's ability to break through a ninja's defenses could depend on how well they can manipulate their mana in relation to the chakra - based defenses. There could also be a concept of chakra - based familiars like the toads in Naruto being combined with the idea of Servant summons in Fate Stay Night.
In a crossover, the power systems would likely have to be balanced. The jutsu in Naruto are very different from the magic in Fate Stay Night. However, if a Fate character were to enter the Naruto world, they might find that their magic is affected by the chakra - rich environment. For instance, a mage's fire spell might be enhanced by the natural energy in the Naruto world. On the other hand, a ninja using chakra might find that they can learn some basic magic concepts from the Fate characters and use it to supplement their jutsu.
The chakra system in Naruto and the powers in Trinity Blood are quite different. Chakra is an energy that can be molded for various techniques. In a crossover, the vampires in Trinity Blood might view chakra as a new form of energy source. They could try to either consume it or find a way to integrate it into their own powers. For example, a vampire might try to use chakra to enhance their physical abilities further.
Well, in a crossover, the power systems would be quite interesting to combine. The devils in Highschool DxD have their own demonic powers which are often based on their individual abilities and their Sacred Gears. In Naruto, chakra is the main power source. If a devil were to enter the Naruto world, they might find that their powers are either enhanced or restricted by the presence of chakra. For instance, a devil's teleportation ability might be affected by the flow of chakra in the area. On the other hand, a ninja with high chakra control could potentially learn to manipulate the energy within a Sacred Gear, if they were to somehow obtain one. This could lead to new and unique power combinations that haven't been seen in either universe before.
In a fanfiction, the power systems could combine in interesting ways. For instance, the chakra in Naruto could be related to the magic in Highschool DxD. Maybe a character could use chakra to enhance their magical abilities. Or, the devil's powers in Highschool DxD could be used to boost the physical abilities of a Naruto character, similar to how the Nine - Tails chakra enhances Naruto's strength.
It's really hard to say who would be the most powerful. On one hand, in Fate Stay Night, Servants like Gilgamesh have incredible power. His Gate of Babylon contains countless noble phantasms. But in the Naruto world, characters like Naruto in his Six Paths Sage Mode are also extremely powerful. He has the power of the tailed beasts and can use all kinds of powerful jutsu. However, if we consider a crossover, it might be someone who can combine the powers from both worlds. For example, if a mage from Fate could learn to use chakra and combine it with their magic, they could be very powerful. Or if Naruto could somehow gain the abilities of a Servant, like the ability to use noble phantasms, he would be unstoppable.
One idea could be to have Naruto characters participate in the Holy Grail War. For example, Naruto himself could be a Servant, perhaps with his chakra being a unique form of mana. His skills like the Rasengan could be reimagined as powerful Noble Phantasms. Another idea is to put the Fate Stay Night characters in the Naruto world. They might have to deal with things like ninja clans and the politics of the hidden villages while also trying to find a way back to their own world.
Naruto's power system is based on chakra, which can be used for various ninja techniques like jutsus. Aiz Wallenstein has her own physical strength and sword - fighting skills. If they were in a fanfiction together, Naruto could use his chakra to enhance Aiz's physical abilities. For example, he could transfer some chakra to her to make her faster or stronger for a short time.
The chakra in Naruto and the skills in Assassin's Creed could combine in various ways. For instance, a character could use chakra to enhance their parkour abilities, making them jump higher and run faster like in Assassin's Creed. Or an assassin could learn to use chakra to perform special attacks similar to ninjutsu.
Well, the chakra system in Naruto could potentially interact with the devil fruits in One Piece. For example, a character with a devil fruit power might be able to use chakra in a new way. The Hokage, being masters of chakra, could study the devil fruits and find a way to either replicate their powers or counter them. Maybe a Sharingan user could predict the movements of a Logia type devil fruit user better.
Rin Tohsaka from Fate Stay Night and Astolfo from Fate Apocrypha. Rin is a serious and intelligent mage, while Astolfo is a carefree and somewhat eccentric Servant. The combination of Rin's no - nonsense attitude and Astolfo's wacky behavior would make for some really interesting and humorous exchanges.
One common theme is power clashes. When different universes collide, the characters with their distinct powers often face off or work together. For example, in a crossover with another action - packed series, the mages from Fate Stay Night might have to deal with new types of combatants.