MC is murdered by followers of a goddess. As an apology, the goddess gives him a new life as a dungeon core. Unfortunately for the readers, he is promptly forcibly bonded by the shittiest dungeon fairy who proceeds to verbally and emotionally abuse him throughout the book while he all but worships her for no reason.
The background music can be annoying at times, but I didn’t have as visceral a reaction as some other readers did.