In a 'halo crossover attack on titan fanfic', there could be many interesting scenarios. For example, Master Chief could team up with Eren Yeager. Master Chief with his superhuman abilities and advanced weaponry could offer new strategies to fight the Titans. The fanfic might also explore how the different cultures and power systems in both Halo and Attack on Titan clash or merge. It could be a story full of action, adventure, and the exploration of two very different fictional worlds coming together.
I'm not sure specifically about really popular 'halo crossover attack on titan fanfic' stories. Fanfic popularity can vary a lot and depends on different fan communities. You might have to search on dedicated fanfic websites to find out which ones are getting a lot of attention.
One common theme is the clash of different power systems. For example, when crossing over with a magic - based series, the contrast between the Titans' brute force and magic is explored.
The story could begin with Optimus Prime leading the Autobots to a new dimension in search of a powerful energy source. This dimension turns out to be the world of Attack on Titan. The Survey Corps mistakes the Autobots for new threats at first. However, Armin, being the intelligent one, quickly realizes that they might be able to help in the fight against the Titans. Meanwhile, Megatron and some Decepticons also arrive. They see the Titans as potential weapons or servants. The Autobots then form an alliance with the Survey Corps. Optimus Prime is impressed by the courage of the humans, especially Mikasa Ackerman. As they battle the Titans together, the Autobots teach the humans about advanced technology, and the humans show the Autobots the importance of unity and tenacity in the face of a seemingly unbeatable enemy.
It could be a very interesting creative crossover. MLP (My Little Pony) has a very different aesthetic and tone compared to Attack on Titan. In a fanfic, it might involve ponies in the world of Attack on Titan, perhaps with their own magical abilities helping or hindering the fight against the Titans. For example, Twilight Sparkle could use her magic to analyze the Titans' weaknesses in a way the Survey Corps couldn't on their own.
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.
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.
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 fanfic could be about Mikasa's transformation into a Titan being a unique situation in the 'Attack on Titan' world. Maybe she has different abilities compared to other Titans. For example, she could retain more of her human consciousness and use her combat skills in Titan form. This would create an interesting dynamic as she tries to protect her friends while being a Titan, which is usually seen as an enemy.