The Fruits Basket characters' unique abilities within their family curse could be combined with Inuyasha's demon powers. For example, if there is a Sohma who can control water in some way as part of their curse, they could team up with Inuyasha to fight a fire - based demon. Inuyasha's demon blood gives him enhanced strength and senses, and when combined with the Sohma's special abilities, they could create a really powerful and unique fighting force.
Inuyasha's sword, Tessaiga, could be used in interesting ways in the Fruits Basket world. For example, if a Sohma is in trouble during their transformation, Inuyasha could use Tessaiga to protect them. On the other hand, the Sohma's zodiac animal abilities could assist Inuyasha in his battles. Like Kyo's cat - like strength and agility could help Inuyasha in a fight against a particularly fast demon.
Tohru's ability to understand and empathize with people could be a great asset in Inuyasha's world. She could help Inuyasha deal with his inner demons, like his hatred for Naraku. In return, Inuyasha's combat skills could protect Tohru and the other Fruits Basket characters from the various threats in his world. Also, the Sohma's ability to transform into animals might give Inuyasha some new strategies in battle. For instance, a Sohma turning into a horse could help him travel faster or carry supplies during a long journey.
Inuyasha's physical strength and combat skills with his sword could be combined with Zatch's magical attacks. For example, Inuyasha could use his speed to get close to an enemy while Zatch casts a spell to immobilize or weaken the foe. Then Inuyasha could deliver a powerful strike with Tessaiga. Another way is that Zatch could use his magic to enhance Inuyasha's attacks, like making Tessaiga's wind scar even more powerful or giving it additional elemental properties.
Kagome's spiritual arrows could be enhanced by Grell's death scythe in a strange way. Maybe their combined powers could create a new weapon or a powerful blast that could defeat a very strong foe. Also, Shippo's illusions could be used to deceive the enemies, and Bardroy's explosives could be set off at the right moment to create chaos among the enemy ranks, which would give Inuyasha and the Black Butler characters an advantage in battle.
Inuyasha's demon blood could interact with the devilish powers in Highschool DxD. His berserker mode when his demon blood takes over could be enhanced or controlled by some of the devil's magic. On the other hand, the characters in Highschool DxD could learn from Inuyasha's group about fighting without relying too much on modern technology. For example, the simple yet effective fighting styles of Sango and Miroku could inspire some of the characters in Highschool DxD to improve their hand - to - hand combat skills.
Well, it could be really interesting. Maybe the characters from Inuyasha end up in the world of Fruits Basket. Inuyasha might be confused by all the Sohma family secrets and the whole curse thing. And the Fruits Basket characters could be scared of Inuyasha at first with his demon side. But then they could learn from each other. For example, Tohru could teach Inuyasha about kindness and acceptance in a different way than Kagome does. And Inuyasha could show the Fruits Basket characters how to be brave in the face of danger.
Yusuke's Rei - gun from Yu Yu Hakusho could be combined with Inuyasha's Tessaiga. For example, Yusuke could use his Rei - gun to enhance the power of Inuyasha's Tessaiga slashes. This would create a more powerful attack against demons. The combination of their raw power would be a force to be reckoned with.
Inuyasha and Kyo would definitely have some interesting interactions. They are both hot - tempered. Inuyasha might see Kyo as a bit of a rival at first. Kyo would probably be curious about Inuyasha's demon form. Another pair could be Kagome and Tohru. Kagome is strong - minded and Tohru is very kind - hearted. They could learn a lot from each other, like Tohru could show Kagome how to be more patient in certain situations.
The characters would have some really interesting interactions. For example, Sebastian would likely be polite yet calculating when dealing with the Sohma family. He might see them as an interesting study, especially those with the animal curse. Tohru, being her kind self, would probably try to befriend Ciel and the others. However, Ciel might be initially suspicious of her overly - nice demeanor, as he's used to a world full of deception.
One interesting storyline could be Inuyasha ending up in the world of Fruits Basket. He might initially be confused by the strange curse and the family dynamics. For example, he could mistake the Sohma's transformation for some kind of demon magic he doesn't understand. His brash nature might clash with some of the more reserved Fruits Basket characters like Yuki, leading to some humorous and tense situations as they try to figure out how to send Inuyasha back to his own world.
If Naruto was in the Splatoon world, his Shadow Clone Jutsu could be used in interesting ways. He could send clones to cover more ground during an ink battle, confusing the enemy. And for the Inkling's part, their ability to swim in ink could help Naruto move around in ink - filled areas more easily. They could also use their ink guns to provide cover for Naruto while he attacks up close.
Well, if Izaya from Durarara and Shikamaru from Naruto were to team up, Izaya's intelligence in manipulating people and Shikamaru's strategic thinking could create some really devious plans. Shikamaru could use his shadow - binding jutsu to physically restrain opponents while Izaya uses his words to mislead and confuse their enemies. Another example is if Celty's shadow powers were combined with Naruto's chakra - enhanced strength. Naruto could use Celty's shadows to extend his reach in battle, like creating shadow - arms that are empowered by his chakra.