Humanity had been driven to the brink of extinction by the man-eating Titans. For more than a century, its greatest line of defense was the Scout Regiment, whose soldiers risked their lives beyond the walls to keep mankind alive. But everything changed when Y/n, a Space Marine of the Ultramarines, was mysteriously transported to their world. Stranded in a land far less advanced than his own, the warrior of Ultramar must find his place among the people of Paradis while proving that neither Titans nor the horrors of their world can stand against the might of an Adeptus Astartes.

Klaus Barthel, a soldier for Paradis Island, lands in Marley as an undercover soldier to infiltrate the enemy under the surname of Jakob Hanns. While he's learning about the enemy and how they operate, he meets Pieck Finger, the Cart Titan while Klaus was writing home to Paradis Island. The two become very good friends, but Klaus starts to have feelings for her and starts to question his loyalty to Paradis Island. Does Pieck, the enemy of Paradis, feel the same about him?

Soon after his mother's death, Elias was on a warpath, wanting to get revenge on the true enemy of Paradis, but little does he know, secrets are about to be revealed.

Elias Heinrich is a childhood friend of Eren, Mikasa, and Armin, located in the Shinganshina District in Wall Maria. When the Colossus Titan destroys the gate at Wall Maria, killing the citizens and destroying the city, Heinrich and his friends were forced out of their home city by Eren's mother, but having the strength of an ox, Elias saved Carla, and helped her to the boat where everyone else was rescued. Eventually joining the 104th Cadet Corps, Elias, Armin, Mikasa, and Eren were trained and made sure to help each other along the way, but around that time, Mikasa starts have feelings for Elias after he treated her with respect all the time they've known each other. How does he react?

It is the year 845, humanity was on the brink of extinction, caused by the Titans. Giant humanoid creatures with insatiable hunger of human flesh. Humanity build these walls to protect themselves from the creatures. They are called Maria, Rose, and Sina. (YN) MacLeod was a childhood friend of Eren Yeager, Mikasa Ackerman, and Armin Arlert in the hometown of Shiganshina in Wall Maria. Until the day came when the Colossal Titan breached the wall, he lost everything. He joins Eren, Armin, and Mikasa in their quest to fight back and retake Wall Maria and swore to return hope to humanity.

Y/N Zöe is the nephew of Hange Zöe, a scientist working for the Survey Corps in the war for humanity. Graduating early from the 103rd Cadet Corps, at the age of 17, Y/N has grown to help his aunt whenever he could while training with his so called "uncle", Levi. One day, he starts to fight alongside the Scouts and was taken really well by his fellow soldiers by how tough he is, but during the trial of one Eren Jaeger, he makes eye contact with a short raven-haired girl named Mikasa Ackerman. The two start getting struck by a thunderbolts due to each other's appearances, but do they get together?

As an orphaned Subject of Ymir born within the nation of Marley, you learned from an early age that life would be cruel and unforgiving, but even that wouldn't be warning enough. Driven by a will to survive, you would soon find yourself cast into a life of service, the life of a Warrior of Marley. But what would become of your life and the mission that followed when you arrived in a foreign land, inhabited by Marley's oldest, most dangerous enemy? Would it be the hell you'd always heard of or would it prove to be anything but? Images used, including cover, are not my property. This story will follow Attack on Titan cannon, leveraging both the manga and anime, as it develops but ultimately may deviate off to establish new storylines over time. Content warning for violence, substance use, and sexual content.

What happens when the humans of a certent wall meet the devil's Bounty Hunter.