Shingeki no Kyojin Wiki describes this:
Attack on Avengers is a one-shot manga crossover between characters from Attack on Titan and Marvel Comics properties. This is the first official Attack on Titan crossover, and the first official Marvel crossover with a manga/anime property. Hajime Isayama created the manga’s story, although Marvel’s C.B. Cebulski wrote the comic itself.
(May contain spoilers)
The idea of crossovers is one of the things we in fandoms desire. Some are hit while others are a miss. Whether it be in video games Marvel vs Capcom and Mortal Kombat vs DC Universe, or comic books like Sonic the Hedgehog/Mega Man or Teenage Mutant Ninja Turtles/Ghostbusters. While these are examples of crossovers, it is hard to believe that a manga like Attack on Titan crossover to the Marvel comic universe. Mangaka Hajime Isayama created the story and the art was done by Gerardo Sandoval. Even though this is a comic, the one-shot was first shown in BRUTUS Magazine in Japan before being released in the West. You can now read this for free in comiXology and Amazon Kindle found in FCBD 2015: Secret Wars #0.
The story begins almost identical to the original Attack on Titan story however, instead of the characters being trapped in a wall, the giant monsters called the Titans mysteriously appeared in New York and are terrorizing the people. The first of the Marvel heroes to fend off the Titans is the Amazing Spider-Man. Later on, the super hero teams Avengers and the Guardian of the Galaxy arrive to fight off the Titans.
The characters involved in this comic has the Marvel Heroes and the titans from Attack on Titans. The Marvel heroes are Spider-Man, the Avengers (Captain America, Iron Man, Black Widow, Hawkeye, and the Hulk), and the Guardians of the Galaxy (Star Lord, Rocket Raccoon, Drax, Gamora and Groot). As for the Attack on Titans, the only characters involved are the Titans themselves as well of the main Titans like Colossal Titan, Armored Titan, and the Female Titan, and none of the human characters. Eren, Mikasa and other scout troops are not in this comic.
Personally, I thought it was a really interesting idea of crossover. Since I am a Marvel fan, I was able to sit down and enjoy some action. However, even though this one-shot combines two of my favorite things, the comic is really short. I was expecting it to be a little longer and see more heroes take down the Titans. Another thing I was also disappointed was not seeing the main characters from Attack on Titan in the Marvel universe. I would love to see Eren and his friends in “comic book” style. I thought the art style was suitable especially on the Titans, it makes them more creepy and hideous. I doubt this will become a comic series but I would like to see the Marvel Heroes and possibly the Villains fight the Titans. Imagine seeing Deadpool getting killed by them or a symbiotic version of the Titans. The same goes for the Eren and the others, I want to see his reaction when he visits New York.
The one-shot comic “Attack on Avengers” is a really fun read. If you like both Attack on Titan and Marvel or familar with them, this story can be easy to understand. The only downside of this comic is that the one-shot is short and only Titans are the only ones present. You can read this for free digitally in comiXology or Amazon Kindle. If you are Marvel fan and want more bonuses, you can save up and buy the entire Marvel: Secret Wars 2015. The entire comic contains the FCBD Secret Wars #0 and the Main issues Secret Wars #1-9. If you got any questions about this comic, comment below or tell me what you thought about.