All his life, Yuuya Tenjou has been the subject of resentment and contempt from everyone around him, even from his parents. To make matters worse, his grandfather—the only person who ever showed him affection—suddenly dies, leaving Yuuya truly alone. Despite facing many adversities, Yuuya does what he can to offer kindness to those who need it—but even the most good-natured people can only tolerate so much abuse. Just when he reaches his breaking point, a flicker of hope appears in the form of a hidden door in his bathroom. This door provides two-way access to an abandoned house in another world, where he instantly gains game-like stats and skills. Moreover, the house once belonged to a sage, which gives Yuuya access to remarkable weapons, equipment, and crops with extraordinary effects. With these newfound blessings, the once-undesirable Yuuya may just reach his true potential and become unstoppable.

Manji is an infamous swordsman in feudal Japan who is known as the "Hundred Man Killer," as he has killed one hundred innocent men. However, there is something far more frightening than his ominous reputation: the fact that he is immortal. This is the handiwork of eight-hundred-year-old nun Yaobikuni, who placed bloodworms capable of healing almost any wound in Manji's body. To atone for his crimes, Manji resolves to kill one thousand evil men. Yaobikuni agrees to this proposal, saying that if he succeeds, she will undo his curse of immortality. Soon after this promise, Manji meets Rin Asano, a 16-year-old girl who requests Manji's assistance in killing those who slaughtered her parents. Initially reluctant, Manji refuses Rin's desperate plea. However, owing to her evident lack of strength, Manji changes his mind and agrees to protect Rin for four years. With this partnership set in stone, the two embark on a perilous journey of bloodshed, vengeance, and redemption, each to fulfill their own life's cause.

Based on COLOPL's school action role-playing game. Set in the year 2045. The world has been contaminated by Irousu (mysterious invaders who suddenly appeared), and humans find themselves restricted and contained. Standing boldly against these invaders are ordinary girls everywhere, without a powerful army or even weapons. The Shinjugamine Girls Academy is a school for these "Hoshimori" (Star Guardians) destined to fight the Irousu. The player is assigned to this academy to train the girls and take back the contaminated Earth. And so, once again, the chimes echo through the sun-strewn schoolyard to mark the beginning of classes today...

Denji is robbed of a normal teenage life, left with nothing but his deadbeat father's overwhelming debt. His only companion is his pet, the chainsaw devil Pochita, with whom he slays devils for money that inevitably ends up in the yakuza's pockets. All Denji can do is dream of a good, simple life: one with delicious food and a beautiful girlfriend by his side. But an act of greedy betrayal by the yakuza leads to Denji's brutal, untimely death, crushing all hope of him ever achieving happiness. Remarkably, an old contract allows Pochita to merge with the deceased Denji and bestow devil powers on him, changing him into a hybrid able to transform his body parts into chainsaws. Because Denji's new abilities pose a significant risk to society, the Public Safety Bureau's elite devil hunter Makima takes him in, letting him live as long as he obeys her command. Guided by the promise of a content life alongside an attractive woman, Denji devotes everything and fights with all his might to make his naive dreams a reality.