After accepting a plea for help to save a small village from marauding skeletons, Rentt stumbles into much more than he bargained for while searching for their source. There’s almost no time to dig into his new discoveries, however—back in Maalt, the blacksmith Clope has an unexpected request of his own. And to top it all off, Rentt has the Silver-class Ascension Exam to prepare for! Being an adventurer is busy work. Getting stronger requires constant effort—you can sleep when you’re dead, after all! Unfortunately, for our unlucky undead hero, that doesn’t apply! The grind never stops in The Unwanted Undead Adventurer Volume 13!

It's been ten years since Rentt Faina, a down-on-his luck Bronze-class adventurer, set his eyes on becoming Mithril-class. Unfortunately, Rentt finds himself helpless when confronted by a legendary Dragon in the Labyrinth of the Moon's Reflection... and is summarily eaten. But Rentt has miraculously reawakened... as a Skeleton?!

With the help of Lorraine, Isaac, Laura, and the rest of his companions, Rentt defeats the vampire Shumini after he attacks Maalt. However, in order to take control of the new dungeon, Rentt has to turn Rina into a vampire and make her his familiar. Both Rentt and Rina have leveled up, so Isaac suggests they try out their newfound abilities. He also offers to teach them about a vampire’s most notable skill: Division. Not everything goes as expected though, because while they were supposed to transform into a bat, Rina transforms into a cat and Rentt into a...tree? Meanwhile, people are flocking to Maalt to study the newly formed dungeon. Not to be left out, Rentt and his companions set out on their next adventure to explore the dungeon’s secrets! Fighting powerful monsters, solving countless mysteries, and becoming stronger! The adventures of Rentt, the undead adventurer who aims to become a Mithril-class adventurer, continues in this thrilling ninth volume!

After Rentt senses something wrong with his familiar, Edel, he and Lorraine leave Hathara and return to the city of Maalt. There they find the city on fire and crawling with thralls. Rentt finds Edel safe beneath the orphanage and learns through him that a single vampire might be the cause of all the chaos. Just as Rentt goes out to help rid the city of the thralls, he runs into the last person he wants to see in this situation—Gold-class adventurer and vampire hunter Nive Maris!

Rentt Faina has achieved Existential Evolution, evolving from a Skeleton into a Ghoul. His next objective: rising the ranks and becoming a Copper-class adventurer! But to do so, Rentt must face his next greatest challenge... A written test?! Using his years of wisdom and the help of two companions, Rentt tackles the challenge head-on. But the worst is yet to come as Rentt finds himself in yet another pickle as he tries to prove his innocence to none other than trusted guild member, Sheila, as she raises concerns over his potential involvement in a recent string of adventurer disappearances. On his journey, he accepts a new quest, leading him to a new area that pits him face-to-face with a mighty monster of the bog! Will Rentt make it out alive to prove his uninvolvment in the disappearances and retrieve a highly-valued medicinal herb? Or is this the second end to the fate of our hero as we know him?

After Rentt, the undead adventurer, passes his Bronze-class ascension exam for the second time, Sheila becomes suspicious and uncovers his true identity. Despite playing dumb, her sincerity convinces him to tell her everything. Now a Bronze-class adventurer again, Rentt takes a special job from an orphanage for a single bronze coin. But before he can fulfill the dangerous and difficult request, he somehow gains a vampiric servant of the rodent kind. In the fourth volume of this adventure fantasy, can Rentt survive his journey into the poisonous and treacherous Tarasque Swamp?!