Siariz no Shugosha

The fantasy manga's story begins when Sabi, decried as a heretic in his town, meets Alice, a person who bears the yoke of a peculiar destiny. Alice chooses him as a Guardian, a chosen partner, before she herself loses her life in a strange occurrence in town. But she is suddenly brought back to life, now with the spirit of the "Holy Priestess" residing within her.

(Source: Anime News Network)

Note: Chapter count includes 5 extras.