Betrayed at the Gala, I Summoned a Demon Queen

Poor scholarship student Kael is humiliated at a banquet—his heirloom crushed, fiancée gone. His blood awakens the ancient Abyssal Covenant. He summons demon empress Lilith, crushes the elite families, and exposes their cult sacrificing humans to dark gods. Kael rises from "trash" to the throne of the night.