Well, it could be about Eren Yeager somehow getting transported to the Naruto world. Maybe he teams up with Naruto to fight against a common enemy like the Akatsuki who have somehow gotten their hands on Titan powers. They would have to combine their unique skills, Eren's Titan transformation and Naruto's jutsu.
In a 'Attack on Titan and Naruto crossover fanfic', perhaps the Hidden Leaf Village is suddenly attacked by Titans. Naruto and his friends are shocked at first, but then they start to figure out ways to combat them. Naruto could try to befriend some of the Titan shifters from Attack on Titan, thinking that there is good in them just like he believed in Sasuke. Together they could work on a plan to stop the Titan invasion and also find a way to send the Titan shifters back to their own world.
One possible plot could be that Naruto and his friends somehow end up in the world of Attack on Titan. Naruto's ninja skills would be really useful against the Titans. For example, his shadow clone jutsu could be used to distract the Titans while the Survey Corps tries to attack their weak points. Also, Sasuke's sharingan might be able to see some hidden details about the Titans that the people in the Attack on Titan world don't know. It would be an epic adventure as they combine their powers to fight the common enemy - the Titans.
Well, it could be about the Survey Corps finding a crashed Cybertronian ship. Maybe the Titans are somehow related to a Decepticon experiment gone wrong. The Scouts would then team up with the Autobots to fight both the Titans and the Decepticons.
Well, it could be about the Survey Corps teaming up with the Avengers. Maybe Eren's titan form could be as strong as the Hulk in a battle against a common enemy like Thanos. The Scouts' ODM gear would be an interesting contrast to the high - tech gadgets of the Marvel heroes.
One possible plot could be that Naruto and his friends are transported to the world of Attack on Titan. Naruto's ability to use chakra and his ninja skills could be used to fight the Titans in a unique way. For example, he could use his Shadow Clone Jutsu to create multiple clones to distract the Titans while the Survey Corps tries to attack their weak points. His Rasengan could also be a powerful weapon against the Titans' tough skin.
A great plot for such a fanfic could be that Mikasa's Titan form is a result of a connection to an ancient Titan power. As she becomes a Titan, she starts to have visions of the past, of how the Titans came to be. She then decides to use this knowledge and her new form to try and end the Titan - human conflict once and for all. Along the way, she has to face her friends who are initially scared of her but eventually come to accept her new form as she proves that she is still the same Mikasa deep down, just in a different body.
One possible plot could be that Naruto and his friends are transported to the world of Attack on Titan. Naruto's skills in ninjutsu would be very useful against the Titans. For example, his Shadow Clone Jutsu could be used to create distractions while the Survey Corps try to attack the Titans' weak points. Also, Naruto's ability to sense chakra could potentially help in detecting Titans from a distance.
One possible plot could be that the Titans somehow cross into Spider - Man's universe. Spider - Man initially mistakes them for some new kind of giant robots or mutants. He tries to fight them using his web - slinging and acrobatic skills. But he quickly realizes they are much more difficult to defeat as they keep regenerating. Meanwhile, some of the Survey Corps members from Attack on Titan also cross over. They team up with Spider - Man, teaching him about the Titans' weak points at the back of their necks. Together, they fight to keep both universes safe from the Titans.
Well, it could be about Sephiroth using his incredible combat skills from Final Fantasy in the world of Attack on Titan. Maybe he teams up with the Survey Corps to take on the Titans. He might use his Masamune sword to slice through the Titans' nape with ease, bringing a new level of badassery to the fight against the Titans.
In this crossover, the Avengers might use their high - tech weapons and superpowers to fight the Titans. For example, Iron Man could blast the Titans with his repulsor rays, and Thor could strike them with his lightning. The Titans, on the other hand, are huge and powerful. Their presence would pose a great threat to the Avengers and the world they are protecting. Maybe the Avengers would have to learn about the Titans' weaknesses quickly to stand a chance in this battle.
One possible plot could be that the ponies accidentally end up in the Attack on Titan world through some sort of magical portal. They then have to figure out how to survive in this harsh environment. They could use their unique pony abilities, like Fluttershy's connection with animals, to try and understand the Titans better. Maybe they could even find a way to communicate with the Titans and find out if there's a way to stop the attacks without all the bloodshed.