Think about Naruto's Nine - Tails chakra mode. If an Assassin were to somehow harness that power, they would become an extremely formidable force. The Assassin could move at incredible speeds and have enhanced strength. Meanwhile, Naruto could learn from the Assassin's training in using different types of weapons. He could combine his own ninja tools with the Assassin's weapons, like attaching a kunai to the hidden blade for a more deadly attack. And the Assassin could teach Naruto how to better analyze his enemies' weaknesses using their own combat analysis skills.
Well, Naruto's ability to use chakra and perform jutsu like the Rasengan could be combined with an Assassin's stealth and parkour skills. For example, an Assassin could use chakra to enhance their speed and jumps while Naruto could learn to be more stealthy using Assassin techniques.
Naruto's shadow clone jutsu would have new applications. Instead of just using it for combat in his own world, in Assassin's Creed 3's setting, he could use the clones for gathering information. The clones could blend in with the crowds in cities like Boston or New York in the game. Also, his Rasengan, which is a powerful attack in his world, could be modified. Maybe he could use chakra control to make it more like a stealth weapon, for example, by making it a smaller, more concentrated blast that can be used to silently take out enemies from a distance.
Ruby's scythe - wielding skills could be enhanced with Assassin's Creed combat techniques. Her speed could be used to quickly assassinate enemies in close combat. Weiss could use her glyphs in combination with Assassin stealth, for example, creating invisible platforms to move around undetected.
Naruto's ability to create shadow clones would be extremely useful in Assassin's Creed Origins. He could send clones to scout areas, distract enemies, or even perform coordinated attacks. His Rasengan could be a powerful finishing move against tougher foes. Also, his enhanced physical abilities due to his ninja training would make him a formidable opponent in the world of assassins.
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.
If we consider the jutsu in Naruto and the power of the Death Note, some jutsu might be able to protect against the Death Note's power. For instance, a powerful barrier jutsu could prevent the Shinigami from being able to access the area where the person targeted by the Death Note is located. On the other hand, the Death Note's power could be used to manipulate the political situation in the Naruto world. Light Yagami's intelligence combined with the Death Note could make him a very dangerous adversary in the world of ninjas. He could use the Death Note to eliminate key leaders and cause chaos, and then use his wits to take advantage of the situation.
Naruto's ability to use chakra and Darth Vader's connection to the Force could potentially create a very powerful combination. For example, Naruto could use his chakra to enhance Vader's lightsaber strikes, making them even more deadly. Or Vader could use the Force to help Naruto better control his Nine - Tails chakra.
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.
The characters' abilities could combine in some really cool ways. For example, Naruto's Rasengan could potentially be infused with the power of a Sacred Gear. This would create a super - powerful attack that has both the destructive force of the Rasengan and the unique properties of the Sacred Gear. Also, the Sharingan from Naruto could be used to analyze and copy the techniques used by the characters in High School DxD. On the other hand, the characters in High School DxD could use their demonic or angelic powers to enhance Naruto's physical abilities, like making him faster or stronger.
Naruto's Rasengan could be combined with Kirby's inhaling ability. Kirby could inhale an object and then spit it out with the force of a Rasengan. Or Naruto could use his shadow clones and have each clone team up with a Kirby ability. For example, one clone could work with Kirby's sword ability to fight enemies.
If we consider the Sharingan ability from Naruto, a character like Sasuke could use it to predict the movements of the zombies more accurately. This could be combined with the strategic thinking of the Highschool of the Dead characters. They could plan out how to best use Sasuke's ability to avoid large groups of zombies or to lead them into traps. The Highschool of the Dead characters might also learn some basic ninja stealth techniques from the Naruto characters, allowing them to move more quietly through the school corridors filled with zombies.