Attack on Titan Reborn or AoT Reborn is a fan-fiction series made by Dorkydoggy, or otherwise known as The Chickenhead. It has OC's littered everywhere as well as dead bodies, blood and magic. Plus some profanity. It is a mixture of the anime and manga. It also has comedy and some music lyrics.
The list of songs is here.
The original chapters can be read here.
AoT Reborn follows the protagonist, Axel Striker, make his way through the apocalyptic situation of Attack on Titan. He watches his friends die and eventually finds himself in the darkened ruins of Shiganshina. Here he stumbles across an old friend Eric Boulder and his dead colleagues. He then goes on a mission with the rest of the Izans to reclaim Shiganshina before the Survey Corps do. They get caught by the Survey Corps and end up helping them. After clearing Wall Maria and going past the wall, the Izans break off from the Scouts who go to the ocean, and instead go into a forest clearing to start building their empire.
The idea is not working so a small group of them wander off to join the war against the Marley.