春の嵐とモンスター (Series) favorite_border

Volume 1: I've got a stepbrother who is too dangerous. Haruno Arashiko is a high school freshman who wants to live like an airhead and not get involved with others as much as possible. Her mother's remarried boyfriend brought her son, Kayak Amamine, a monster junior high school student who is the type to throw people around town! Apparently, Kayak has a situation...? The story of a brother and sister who have a bumpy relationship begins, turning the ordinary into the extraordinary!