One could imagine a fanfiction where Naruto, with his fox - like powers, teams up with an assassin inspired by Altair. Maybe they are on a quest to stop a powerful evil that threatens their respective worlds. They could learn from each other's skills, Naruto teaching Altair - like character about chakra, and the assassin teaching Naruto some stealth techniques.
The fanfiction could focus on how Naruto's ninja skills blend with the Fox Assassin's abilities in an Altair - style setting. They might be in a city full of political intrigue and have to use stealth and combat skills. Naruto could use his shadow clones to gather information, while the Fox Assassin uses his speed and agility.
If Altair was emotionally hurt as a child, say by the loss of his parents. He might be cold and distant at first in the assassin brotherhood. But as he grows, he starts to open up. He uses his emotional pain to understand the motives of his targets better. For example, if he's going after someone who also lost a loved one and turned bad. He can empathize yet still do his job as an assassin.
If you like novels about assassins, I can recommend I Have Countless Servants to you. The protagonist of this novel, Kevin, was also a person who had transmigrated to a different world. He had obtained the ability to summon various demonic spirits, including the character of the Assassin's Soul, Tell. He used the demonic spirit's ability to fight against powerful enemies and finally reversed the situation of the entire world. If you like this kind of story, then this novel will definitely attract you. I hope you like my recommendation, Mwah ~😗
One idea could be that Altair, after being hurt as a kid, is taken in by an assassin. He trains hard to overcome his pain and fear, gradually becoming a skilled assassin. He might have a mentor who helps him channel his anger into his training and missions.
She would likely be highly skilled in combat, just like Altair from the original. She might be very agile, able to quickly scale buildings and move through crowded city streets unnoticed. Intellectually, she'd be sharp, able to analyze situations and come up with strategies on the fly. And she'd have a strong sense of justice, being committed to the Assassin's cause of fighting against the Templars' tyranny.
You can try searching on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms usually have a wide range of fan - created content, including stories about Altair and Malik from Assassin's Creed.
One interesting element is the combination of different combat styles. Altair's assassin skills from Assassin's Creed and the unique fighting styles in RWBY can create really exciting battle scenes in the fanfic.