His jutsu could be seen as a form of magic in the Grail War context. For example, the Rasengan might be like a powerful magical attack. His ability to sense chakra could be adapted to sense magical energy. And his Sage Mode would give him enhanced physical and magical capabilities.
If Naruto is summoned in the Holy Grail War fanfic, his abilities would have to be adjusted to fit the new setting. His ninjutsu, which is based on chakra in his world, would likely be translated into a form of mana - based magic. His ability to run on walls and water could be due to a special magical trait. His summoning jutsu might also work differently, perhaps summoning creatures more in line with the Grail War's lore. Also, his Kyuubi - influenced powers would be a major factor. It could be seen as a powerful and dangerous form of magic that other Servants would fear or try to control.
Well, Naruto's powerful jutsu and combat skills would make him a formidable Servant. He could use his Shadow Clone Jutsu to confuse his opponents and then hit them with a Rasengan. His strong will and determination would also play a big role in the battles of the Holy Grail War.
Naruto's abilities would be quite formidable in the Holy Grail War fanfic. His speed and strength, enhanced by his ninja training, would give him an edge. His jutsus like the Summoning Jutsu could bring in powerful allies. However, he'd need to be careful as some Servants might have abilities to counter his attacks.
If Naruto is summoned in the Holy Grail War fanfic, he would bring his unique ninja skills. His shadow clone jutsu could be used to confuse opponents and gather information. Also, his Rasengan could be a powerful offensive move against other Servants. He might have a hard time understanding the rules at first, but his determination would make him adapt quickly.
His abilities would be a game - changer. His strategic mind could outwit many of the other Masters. His use of modern weapons combined with his Servant's powers would be a deadly combination.
Naruto's physical abilities like his speed and strength from being a ninja would be very different from the magical abilities in the Potterverse. For example, he can move very fast without the need for a broomstick like wizards use for flying.
His character would become more assertive as a master. He'd have to take charge and make decisions quickly, which would be a change from his sometimes indecisive self. He'd also have to be more cunning to outwit the other masters.
In a fanfic where Kiritsugu is summoned in the 5th Grail War, he would bring his own set of skills and motives. His skills as an assassin would come in handy. He might try to figure out the true nature of the Grail this time around, especially after his experiences in the previous wars. His relationship with other Servants could be complex. Some might respect him for his past achievements, while others might see him as a threat. And his actions would likely be guided by his own moral code, which, although not entirely conventional, has its own logic.
Naruto's chakra could be affected in different ways. Maybe his chakra would take on some properties of the Xenomorphs' acidic blood. So, when he uses certain jutsu, it could have an acidic effect as well. Also, his ability to sense danger could be enhanced. The Xenomorphs have a natural sense of stealth, and Naruto could inherit this, making it even harder for enemies to surprise him. He could also use his shadow clones in more creative ways, like using them as decoys to draw out the Xenomorphs' attacks and then counterattack.
I think Naruto as a Servant could be extremely powerful. His ability to access the Nine - Tails' chakra gives him a huge boost in strength, speed, and endurance. Plus, his Rasengan and other ninjutsu would be formidable attacks. His never - give - up spirit could also translate into a high - level of tenacity in battle, making it hard for opponents to defeat him.
There were a few novels that met this requirement, such as Sword Immortal who joined the chat group, Infinity from the Giants, and The Final War of the Apocalypse. The protagonists of these novels were involved in the Holy Grail War, but the main content of the novels was not the Holy Grail War. It involved different worlds and storylines. If you're interested in these novels, you can read them. I hope you like my recommendations.