Ryuusei saves a demon girl and ends up dying so she shares half of her power with him and now he's basically a demon too. If they separate, he dies. If they don't find the one who summoned her within a year, he dies too.
Airi Katagiri, is a high school girl who cannot ignore people in trouble. One day while on her way to school, a magic circle appears under Airi's feet and she is sent to the Demon World. In the Demon World, demons are performing a ritual to revive the Demon Lord, which summons Airi. Seeing her, the demons think that they have failed to revive the Demon Lord, but it turns out that Airi has the power of the Demon Lord. In order to find a clue to return to her original world, she decides to become the Demon Lord. (Source: Natalie, translated)
Kaminari Seijuro is a fearsome Yakuza of the Jinbo-gumi, who operate in the Roppongi Red Light District of Tokyo. But what Kaminari really longs for is the Game of Kings: Golf. If he can survive the violent battles over control of Tokyo's night life, hopefully he can fit in 18 holes, too. (Source: Shueisha, translated)
Souhei Asakura is a detective whose job is to get rid of the "pests" in society that harm others. However, his catch phrase is "Ah, I want to die"...and he's a downer, loves to eat eggs, plus he uses a rope to snare these "pests" - literally! With unconventional methods and a rope to tie up the bad guys, Asakura teams up with a young police man named Keiichi Tsuji under the orders of his somewhat sadistic boss Miyuki Kanou. *Note: Includes 1 extra chapter.*
We rejoin Tooru heading into the 21st century, some 10 years after he first discovered his power to become invisible. Sometime in his 2nd year of high school, his powers stopped working, and he's managed to become a productive member of society. Then, one day, his aunt asks him to clean up the freezer, and he discovers an old container of salmon roe that had frozen away in a corner. Miraculously, the roe in this container still activates his power! And of course, Tooru's still not quite restrained enough to not use this power again...
Muscle Island. No civilized equipment can be brought here, and the only thing you can rely on is your own well-trained muscles! Shibaki and Narita are dispatched as observers to the island, which is crowded with such macho people. What miracles are woven into the well-trained human body that they see...? (Source: Shueisha, translated)
"We're murderers." Mayu is an ordinary high schooler who goes to an all-girls school. She lives a fulfilling high school life with her friends, Oto and Yuu. However, one day, Mayu and Yuu witness Oto pushing her homeroom teacher over, who then falls unconscious. Oto says that it's just a temporary loss of consciousness, but...!? (Source: Young Jump, translated)
*Note: Includes 12 extra chapters.*

