One possible storyline could be that Naruto, with his ability to teleport and his powerful ninjutsu, senses Mikasa in danger in the Attack on Titan world. He quickly arrives, uses his Rasengan to defeat the Titans surrounding her. Then he takes her to safety and they form an unlikely friendship, with Naruto sharing his experiences of fighting for his village and Mikasa being amazed at his powers.
In this fanfiction, Naruto might be brought into the world of Attack on Titan through some sort of interdimensional rift. When he sees Mikasa about to be overrun by Titans, he unleashes his Shadow Clone Jutsu. The clones swarm the Titans, distracting them while Naruto swoops in and rescues Mikasa. They then start to communicate, Naruto trying to understand the strange world she lives in and Mikasa learning about Naruto's world of ninjas.
Perhaps Naruto is on a mission in a new dimension and stumbles upon Mikasa's fight against the Titans. His superhuman speed allows him to reach her in time. He uses his Sage Mode to gain an edge over the Titans and saves Mikasa. Afterward, they team up. Naruto teaches Mikasa some ninja techniques, like how to better use her agility in combat, and Mikasa shows Naruto how to handle the 3D Maneuver Gear more effectively.
Well, Naruto could use his Nine - Tails chakra to create a powerful shield around Mikasa when the Titans are attacking. This would protect her from their attacks. Then he could use his chakra arms to grab onto nearby buildings and swing them both to safety.
One possible storyline could be that Supergirl is trapped in a dimension where her powers are nullified by some sort of kryptonite - like substance from another universe. Naruto, with his shadow clone jutsu and rasengan, manages to find a way into this dimension. He uses his clones to search for the source of the power - nullifying element while he battles the minions that are guarding it. Eventually, he destroys the source, and Supergirl's powers return, and they both escape the dimension together.
In a more AU (Alternate Universe) setting, they could be in a world where the titan threat doesn't exist. They are just two normal people in a small town. Eren has been in love with Mikasa for a long time but was too shy to act. One day, during a local festival, he finally gathers the courage to kiss her under the twinkling lights.
Perhaps Anko is trapped in a genjutsu and Naruto uses his own experience with breaking free from illusions to save her. He could sense her distress and use his chakra to disrupt the genjutsu, freeing Anko. This would show Naruto's growth and his ability to help those in need, even a more experienced ninja like Anko.
One great Naruto and Mikasa fanfiction is 'The Unexpected Alliance'. In this story, Naruto somehow finds himself in the Attack on Titan world and teams up with Mikasa. It's really interesting to see how their different skills and personalities interact. The author does a great job of keeping both characters in - character while also creating a new and exciting plot.
Well, in the original, Haku and Zabuza die. But in this fanfiction, Sakura's actions change that fate. This is a huge deviation as it completely alters the expected outcomes for those characters.
It's also about the characters themselves. Naruto is this energetic, optimistic guy who never gives up, while Mikasa is more reserved and focused on protecting her loved ones. Their different personalities can lead to some great character development and interactions in fanfiction. For example, Naruto could inspire Mikasa to be more open, or Mikasa could teach Naruto some new combat strategies.
One good Naruto Mikasa fanfiction could be a story where they meet in a crossover world. Maybe Mikasa is on a mission in the Naruto universe and she teams up with Naruto to fight a common enemy. They start off as strangers but gradually learn from each other's skills and values.
One key moment could be when Naruto jumps in front of a fatal attack aimed at Konan. His quick reflexes are crucial here. He takes the hit or deflects it using his own skills, like his shadow clone technique to create a distraction and then save Konan.
The fanfiction where Naruto saves Yugao could have various scenarios. It could start with Yugao on a mission that goes wrong. Naruto, being the hero he is, might sense her distress. He could then embark on a journey to find her. Once he does, he might have to fight off a group of rogue ninjas. His Rasengan could be the decisive move to defeat the enemies and save Yugao. This event could also have an impact on the overall ninja world in the fanfiction, perhaps leading to new alliances or revelations about Yugao's past.