Death Loop Reijou wa Ikinokoru Tame ni Ryoute wo Chi ni Someru You desu

"Until the demon lurking among the participants is slain, this game shall not end." Lady Hermina, the daughter of the Count Einhorn, finds herself entangled in a deadly game called the "Summoning Ritual of a Wicked God" within an ancient northern castle, alongside her childhood friend and maid, Char