A squid-like creature, known as a Happian, leaves his home planet with the desire to spread happiness across the universe. He lands on Earth, but quickly finds himself in danger of captivity by its inhabitants. Fortunately, he is found by an unsmiling little girl named Shizuka Kuze, who feeds him and names him Takopii. Feeling indebted, Takopii decides to do everything in his power to bring a smile to her face. The task is easier said than done, however. Shizuka is bullied by her classmates, she does not have a father, and her mother is never home—though the gravity of these issues flies over the naive Takopii's head. Even so, Shizuka does have one source of happiness: her dog Chappy. The connection Shizuka and Chappy share only increases Takopii's desire to make the girl smile. While Takopii's attempts to lift Shizuka's spirits lead to unintended consequences, he is determined to take things into his own tentacles, test his understanding of human beings, and achieve his goal of spreading happiness.

Takeru Narihira is a lone wolf delinquent who spends his days getting into fights, avoiding friendships, and being captivated by a mysterious girl named Tsukimiya—someone he's only ever seen in his dreams. One day, a sudden accident sends him tumbling off a cliff. When he regains consciousness, he finds himself in Denji Heian-kyou, a futuristic version of the ancient capital, where advanced technology and mysticism coexist. This world is under the protection of the legendary onmyouji, Abe no Seimei—and to Takeru's shock, Tsukimiya is real and living in this very place. Just as he begins to revel in this fated encounter, a deadly black mist known as Yamikaoru descends, bringing forth monstrous beings called Oni. In the chaos, both he and Tsukimiya are killed—only for Takeru to awaken once again in Denji Heian-kyou. Realizing he has somehow slipped through time, Takeru resolves to defy fate. To protect Tsukimiya from her doomed future, he turns to Abe no Seimei to train in the art of onmyou-jutsu. Now, as an onmyouji himself, he must fight to rewrite destiny and uncover the truth behind this strange new world.

A number of inexplicable phenomena have been plaguing the town of Domori. In order to protect the town's children, a new homeroom teacher known as "Nube" arrives. Normally gentle and a bit outgoing, Nube has a secret side: he is, in fact, the only psychic teacher in Japan. Rumor also has it his left hand is possessed by a demon!
Hell's messenger of justice is here to take on the school's seven mysteries, ghosts, and evil spirits attacking his students. This occultist action story starts now!

Alicia, who had dreamed of becoming a hero since childhood, is chosen by the king as one of the thirteen heroes. Armed with a legendary sword, the heroes set out to defeat the Demon King Clevatess. However, their recklessness triggers a terrible crisis that could wipe out all of humanity on the continent of Edsea. Now, the world's only hope lies with a baby entrusted to the Demon King.