Contracted Skeleton Overlord

After dying and waking up as a talking skeleton, he unlocks an SSS devouring system—whatever he eats makes him stronger. When a genius campus queen accidentally summons him, the whole school laughs at their “trash contract.” But as deadly dungeons and cruel enemies close in, this useless skeleton begins devouring bosses, evolving fast, and proving he was never trash—he was a king waiting to awaken.