For RWBY, Ruby is a popular choice. Her optimism and leadership, combined with her powerful scythe - wielding skills, can be an interesting contrast or complement to the Akatsuki characters. In fanfiction, she might be the one to try and understand the Akatsuki's motives or be the first to offer them a chance at redemption.
A fanfiction could also explore a world where the Akatsuki and RWBY teams are merged into one super - team. The different fighting styles and abilities would make for really exciting battles. Characters like Itachi with his Sharingan and Blake with her semblance could combine their skills in stealth and combat to outwit their enemies.
Itachi is often a popular character. His complex backstory and powerful abilities make him an interesting addition to any fanfiction. In RWBY - Akatsuki crossovers, his Sharingan could have unique interactions with things like the Grimm or the Aura in the RWBY universe.
One interesting story could be about a crossover adventure where members of Team Akatsuki from Naruto end up in the RWBY universe and have to team up with RWBY characters to fight a common enemy. They might use their unique jutsu and abilities in combination with the Huntsmen and Huntresses' skills.
There are so many fanfiction stories out there, and 'akatsuki find a baby' is a unique enough idea that it could have been explored in various ways. For example, in some fanfictions, the baby could be a key to some hidden power or prophecy that the Akatsuki is interested in. Or perhaps the baby is from an enemy clan, and the Akatsuki has to decide what to do with it. To find the exact fanfiction you're looking for, you could try searching with specific keywords related to the Akatsuki members involved, or any other details you might remember about the story.
Well, in this fanfiction, it could be that Akatsuki has a change of heart. Some members might realize that Naruto represents a hope for the ninja world in a different way than they initially thought. So they step in to save him when he's in a really tough situation, like being trapped in a powerful jutsu or surrounded by a large number of enemy ninjas. They use their own unique skills, like Kisame's water jutsu or Itachi's Sharingan abilities to fight off the threats.
Well, it could be that there's a plot device like an ancient artifact. This artifact might have the power to draw out and combine the Akatsuki powers. The Akatsuki members themselves might be tricked into contributing their powers to this artifact, and then the protagonist or an antagonist gets hold of it and gains all those combined powers. It's a common trope in fanfiction to use such magical or mysterious items to bring about extraordinary power combinations.
Pain would still be a likely candidate. His Rinnegan gives him a powerful and commanding presence. He has the ability to see the big picture and make strategic decisions for the group.
One great Naruto Shippuden Akatsuki fanfiction could be about a new character who infiltrates the Akatsuki. This character might have a special power that the Akatsuki wants to use for their own ends. The story could explore the moral dilemmas the character faces as they get closer to the Akatsuki's inner workings. They could start to question whether the Akatsuki are all bad or if there's some truth to their motives.
Yes, there are several fanfictions with this concept. In these fanfictions, Naruto's character often undergoes significant changes as he joins the Akatsuki. His motives for joining can vary from seeking a different path to having been influenced by certain events or characters. It's an interesting twist on the original Naruto storyline.