LAIDBACKERS: THE NOVEL

The anime takes place in modern Kyoto. Kumi is a college student who moves to Kyoto in order to take over the candy store inherited from her late grandmother. The house accompanying the candy store was supposed to be unoccupied, but there Kumi meets three women (Harami, Mai, and K) and a dog. The four are heroes who were reincarnated from their world into this one. One day the former demon king, who messed up her reincarnation and is now in the form of an elementary school student, appears and asks, "will you please collect the demon king fragments together with me?"

(Source: Anime News Network)