Masahiro Setagawa is a hopeless teenager who is often used by the neighborhood bullies as an errand boy. Defenseless, Masahiro knows that nobody will ever save him. However, his life drastically changes when he meets Kousuke Ooshiba, a man known as the "Bear Killer," who takes down neighborhood gangs. A year later, Masahiro and his former friend, Kensuke Ooshiba, attend high school, only to find that Kousuke is their math teacher. While the three grow closer, Masahiro starts to view Kousuke as his "hero," and Kousuke develops an urging desire to protect Masahiro. However, their normal lives take a turn when Kensuke's childhood friend, Asaya Hasekura, returns, seeing Kensuke as more than just a friend, much to his surprise. Will the three boys be able to live a regular high school life? Or will forbidden love keep them apart forever?

Rumors stir throughout the land: when the wielder of the black sword draws his dark blade, all who stand in its path are torn asunder...! Köinzell, the mysterious young boy who carries the black sword, undeniably wields it with exceptional skill, but can he truly be responsible for the bloody rumors? Pursued by the Traitorous Lances, four powerful warriors who were thought to have been defeated by the Seven Heroes, the strength of the young swordsman will be tested to its limit. At battle's end, only the shocking truth of Köinzell's quest will stand above the corpses of his enemies... An epic fantasy on the grandest of scales!

As another school year begins drawing to a close, the third-year high school students move steadily toward the next milestone of their lives: graduation. Among them are Mio Natsume, a girl burdened with lingering feelings; Hazuki Morikawa, a member of the concert band but distant from the others; and Haruto Souma, an athlete obsessed with baseball. Meanwhile, second-year student Ena Komiya seeks to revive the photography club to its former glory, refusing to let the organization be disbanded. Though this group lacks a strong connection with one another, their lives suddenly cross paths with the arrival of a third-year transfer student. While a transfer so close to graduation is unusual for most, it is business as usual for Eita Izumi. Due to his father's work, he has never been able to stay in one place for very long. But as luck would have it, their most recent relocation has returned Eita to his hometown for his final semester of high school. For better or worse, it also sparks the rekindling of old relationships left behind in the past. With graduation already causing its own share of anxieties, Eita's sudden arrival brings these students' carefree days to an abrupt end. Long-forgotten memories, deeply buried emotions, and inspiring new passions—everything is brought to light in their bittersweet final semester. [Written by MAL Rewrite]

Mahiru Shirota firmly believes that simple is best and troublesome things should be avoided at all costs. It is troublesome to do nothing and regret it later—and this ideology has led the 15-year-old to pick up a stray cat on his way home from school. As he affectionately names the feline Kuro, little does he know that this chance meeting will spark an extraordinary change in his everyday life. One day, Mahiru returns home to find something quite strange: a mysterious young man he has never seen before. His subsequent panic results in the uninvited guest being exposed to sunlight and—much to Mahiru's shock—transforming into Kuro! Upon revealing himself as a mere lazy shut-in vampire, Kuro promises to leave once night falls. However, one disaster after another leads to Mahiru accidentally forming a contract with his new freeloader, dragging him into a life-threatening battle of supernatural servants and bloodthirsty beings that is anything but simple. [Written by MAL Rewrite]