Kochira Last Boss Maou Shiromae "Kyoukai"

Sacred, the youngest High Priest in history, is stationed at the "Last Church" located before the Demon King's castle. His duty is to await the arrival of the Hero. In the interim, he must coexist with the nearby Demon Lord's forces. Using his rhetorical abilities, he calms the Gatekeeper and even persuades the initially hostile Demon Lord Stella through his use of a rod of light. Over time, Stella and her younger sister begin visiting the church. Sacred, regarded with trust by both the Demon King and the Hero, begins a quiet life in this remote location.