Since the discovery of "Samon Syndrome" 30 years ago, thousands of young people have traveled to fantasy worlds, the few returnees managing to keep the special abilities they acquired in those parallel universes. Akatsuki Ousawa, known as the "Rogue Hero," discards his peaceful life in the fantasy world Alayzard to face new challenges upon returning to Earth. He comes back with Miu, the daughter of the Demon King he defeated, and is now forced to hide her true identity by having her pose as his little sister. The two soon join Babel, a special school designed for those who have acquired special abilities and magical powers through their journey to a fantasy world. Babel was seemingly founded to train young interdimensional travelers and "guide them to the right path for the sake of humanity and themselves," but its true purpose remains unclear to the pseudo-siblings. Will Akatsuki and Miu be able to overcome the hostile, powerful student council and uncover the forces at play behind the scenes? [Written by MAL Rewrite]

At the Battle of Sekigahara in 1600, Toyohisa Shimazu is the rearguard for his retreating troops, and is critically wounded when he suddenly finds himself in a modern, gleaming white hallway. Faced with only a stoic man named Murasaki and hundreds of doors on both sides, Toyohisa is pulled into the nearest door and into a world completely unlike his own. The strange land is populated by all manner of fantastical creatures, as well as warriors from different eras of Toyohisa's world who were thought to be dead. Quickly befriending the infamous warlord Nobunaga Oda and the ancient archer Yoichi Suketaka Nasu, Toyohisa learns of the political unrest tearing through the continent. Furthermore, they have been summoned as "Drifters" to fight against the "Ends," people who are responsible for the creation of the Orte Empire and are trying to annihilate the Drifters. As the Ends grow more powerful, so does the Empire's persecution of elves and other demihumans. It is up to Toyohisa and his group of unconventional heroes to battle in a brand-new world war to help the Empire's subjects, while protecting the land to claim for themselves and challenging the Ends. [Written by MAL Rewrite]

Otaku siblings Tamotsu and Niwaka Denkigai are shopping in Akihabara when it is overrun by vampiric cosplaying monsters! These creatures, known as "Bugged Ones," can possess anyone they bite and soon they begin causing mayhem across the city. As Tamotsu finds himself at the mercy of one of these creatures, he is rescued by the mysterious baseball bat-wielding Matome Mayonaka. Together, they fight through several more encounters with the Bugged Ones, but before long, Tamotsu is fatally wounded protecting Matome. With no other choice, she revives him as a high level Bugged One—just like her! Tamotsu and Matome, along with excitable otaku cosplayer Arisa Ahokainen, make up the group "The Electric Mayonnaise" and they begin dispatching the Bugged Ones in the only way they know how: by ripping off their clothes and exposing them to sunlight! [Written by MAL Rewrite]

During his summer vacation, middle school student Nagasumi Michishio travels to the Seto Inland Sea. One day, while swimming at Mio Sun Beach, his leg suddenly cramps. No one is close enough to notice his desperate screams for help, and so he sinks into the ocean, where he is left to drown alone. Just as he loses consciousness, however, a mermaid appears and saves his life. That night, Nagasumi is visited by his savior, a girl who introduces herself as Sun Seto—a mermaid from a yakuza family. As it turns out, under mermaid law, a mermaid whose identity is revealed to a human must be punished by execution. To avoid this harrowing outcome, the Seto family propose a solution: Nagasumi must marry Sun or die at the hands of Gouzaburou, Sun's father and boss of the Seto clan. Faced with no other option, Nagasumi takes her hand in marriage. Now, the newlyweds face the difficult task of keeping their relationship secret. Between Gouzaburou's unending attempts on Nagasumi's life and the eccentric antics of a slew of antagonists, a genuine and innocent love blossoms between the pair as they adapt to their new life. [Written by MAL Rewrite]