Rentt Faina, a low-ranking adventurer in the town of Maalt, dreams of achieving greatness but is stuck performing menial tasks due to his lack of skill and resources. While exploring a dungeon, he encounters a powerful dragon and is killed. Instead of dying, Rentt awakens as a skeleton, retaining his consciousness and memories. Confused but determined, he begins to adapt to his new undead existence, discovering that he can grow stronger by absorbing the essence of monsters. This ability allows him to evolve his undead form, gradually regaining human-like features while retaining his monstrous powers.

As Rentt navigates his new life, he seeks to understand the nature of his transformation and the mysteries surrounding the dungeon where he died. Along the way, he encounters Lorraine Vivie, a skilled mage and scholar who becomes his ally. Despite recognizing his undead nature, Lorraine supports Rentt, aiding him in his quest for answers and helping him maintain his secret identity. Rentt’s journey intertwines with the broader world of adventurers, guild politics, and ancient legends, as he uncovers clues about the dungeon’s origins and the forces that may have influenced his transformation.

The narrative explores themes of identity, perseverance, and the pursuit of knowledge, as Rentt balances his dual existence as both an adventurer and an undead being. His evolving abilities and relationships with other characters, including fellow adventurers and guild members, drive the story forward. The series delves into the intricacies of the adventurer’s guild system, the hierarchy of monsters, and the lore of the world, creating a rich backdrop for Rentt’s personal journey. Through his trials, Rentt gradually gains strength and influence, challenging the limitations of his former life while grappling with the moral and existential questions posed by his undead state.