Hoshishoku ni Watashi o

Momen, who leads their people as a priest in a broken church, is bitten one day by the vampire Wata. They're almost on the verge of life and death, but Wata's bite imprints a cursed pattern on himself. The two are connected by a curse that dictates Wata can only suck Momen's blood.

Wata desperately takes care of Momen, and they live together for a time. As the two struggle to stabilize their lifeline and break the curse, their relationship gradually changes.

[translated from official website]