One possibility is that Sephiroth's presence in the Attack on Titan world disrupts the balance. His otherworldly abilities attract the attention of both the military and the Titans. The Titans might be drawn to him, thinking he's a new type of prey. Meanwhile, the military is both in awe and afraid of him. This could lead to a series of events where Sephiroth has to navigate this new world while also dealing with his own motives and the chaos he's causing.
The plot could involve Sephiroth being somehow transported to the Attack on Titan universe. He initially views the Titans as mere nuisances compared to the foes he's faced in his own world. However, as he gets involved, he discovers the complex politics and the desperation of the people. He might decide to use his powers to not only fight Titans but also to change the power dynamics within the walls.
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.
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.
One possible plot could be that the Avengers are somehow transported to the world of Attack on Titan. They team up with the Survey Corps to fight the Titans. Iron Man could use his high - tech suits to take on the Titans from a distance, while Captain America leads the ground troops along with Eren and his friends. Thor could use his lightning powers to stun the Titans, making it easier for the others to attack.
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.
One possible plot could be that the Titans are actually some kind of ancient, corrupted Transformers. The Survey Corps discovers a hidden technology that has the power to control or at least influence the Titans. Eren, with his Titan - shifting ability, might have a special connection to this technology. The Autobots arrive on the scene, initially seen as a threat by the humans. But as they learn about the Titans, they team up with the Survey Corps to fight against this common enemy, using their advanced weaponry and Eren's unique power.
Well, one possibility could be that Sakura's medical skills from Naruto are used in the Attack on Titan world. Maybe she helps heal the injured soldiers who fight Titans. Her strong will and combat skills could also make her a valuable addition to the Survey Corps. For example, she could use her chakra to enhance her physical abilities during Titan battles.
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 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.
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 interesting plot could be that the Survey Corps discovers a titan that has some sort of connection to the Kaiju from Pacific Rim. Maybe the titan has a similar biology or origin. They could then team up with the Jaeger pilots to study it and figure out how to defeat both the titans and the Kaiju. The Jaeger pilots could teach the Survey Corps about their advanced technology, while the Survey Corps shares their knowledge of fighting in a more primitive, yet effective way against the huge and dangerous enemies.
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.