Mahiro Yasaka is just an ordinary high school student, until one day he is suddenly attacked by a dangerous monster. Just when everything seems to be lost, he is saved by a silver-haired girl named Nyaruko, who claims to be the shape-shifting deity Nyarlathotep from horror author H. P. Lovecraft's Cthulhu Mythos, sent by the Space Defense Agency to Earth. She explains to Mahiro that the creature chasing him was an alien called Nightgaunt, who had planned on abducting and selling him as a slave. After rescuing him from the alien, the Lovecraftian deity falls madly in love with Mahiro and forces herself into his household, much to his chagrin. Moreover, they are soon joined by two others from the fictional universe: Cthuko, a girl obsessed with Nyaruko, and Hasuta, a young boy easily mistaken for a beautiful female. Together, the three eccentric aliens protect Mahiro from the various extraterrestrial dangers that threaten both his and Earth's well-being, all the while making his life a living hell. [Written by MAL Rewrite]

Yuu Koito has always been entranced with romantic shoujo manga and the lyrics of love songs. She patiently waits for the wings of love to sprout and send her heart aflutter on the day that she finally receives a confession. Yet, when her classmate from junior high declares his love for her during their graduation, she feels unexpectedly hollow. The realization hits her: she understands romance as a concept, but she is incapable of experiencing the feeling first-hand. Now, having enrolled in high school, Yuu, disconcerted and dispirited, is still ruminating over how to respond to her suitor. There, she happens upon the seemingly flawless student council president, Touko Nanami, maturely rejecting a confession of her own. Stirred by Touko's elegant manner, Yuu approaches her for advice, only to be bewildered when the president confesses to her! Yuu quickly finds herself in the palm of Touko's hand, and unknowingly sets herself on a path to find the emotion which has long eluded her.

Megumin is a young and passionate wizard from the Crimson Demon Village, a remote community of mages with red eyes and a flair for the dramatic. She has devoted her life to mastering explosion magic, a powerful but impractical spell that leaves her drained of mana and unable to move for the rest of the day. Regardless, she refuses to learn any other skills. Along with her childhood friend and self-proclaimed rival, Yunyun, Megumin enrolls in the Red Prison: a prestigious academy for Crimson Demon magic users. There, she learns more about the secrets and history of her clan, as well as the threats and challenges they must face. As she polishes her power at the Red Prison with the help of her loyal familiar Chomusuke and her adorable little sister Komekko, Megumin aims to become the greatest explosion wizard of all time!

"Dear diary... I got reincarnated as a slime." Even in another world, lives aren't always on the line. There's plenty of work to be done, from feeding the community and forging the items the community needs; as well as plenty of play ...and hijinks throughout! Join Rimuru and friends as they kick back and enjoy their daily lives.