A dungeon belonging to a succubus queen is raided. She and all her servants are cut down, including a weak skeleton warrior with no notable achievements to his name. But right before he dies, he gains the ability to level up and gain power with experience. The first benefit this grants him is the ability to resurrect on death.
The skeleton soldier wakes up twenty years previously, on the day a necromancer first raised him from his grave. After he watches her cut down by bandits and is killed again, he discovers his strange "level up" abilities and slowly gains enough experience to save the necromancer.
With a second chance at life, he decides to continue on until he can meet the succubus who he so cherished. But the world is not kind to skeleton soldiers, and he faces danger at every turn.
This manwha provides examples of:
- Alas, Poor Villain: The spider queen dies trying to save her last egg.
- Ape Shall Never Kill Ape: The skeleton soldier tries not to kill other skeletons. They don't share this sentiment, so he has to kill them in self-defense.
- Asshole Victim: A group of thugs who run an orphanage where they abuse the children and sell them to corrupt nobles gets kill by Lime when an orphan girl ran away from the thugs and seeks protection at Lime's orphanage where the thugs demand not only the girl back but also want the rest of orphans under his care as to sell them as well.
- Bitch in Sheep's Clothing: Rena is introduced planning to kill the other two members of her party and steal their riches. However, she grows attached to the skeleton soldier over time.
- Brainwashed and Crazy: Staying inside a dungeon too long causes skeleton soldier to assimilate with it and view any intruders as enemies to be slain for the sake of his succubus mistress. Before, he was very willing to just let people go unless they attacked him and would even let them run if they did, but when the dungeon is affecting him he even attacks his ally Rena without a second thought.
- Cool Big Sis: Rena acts as one towards the younger children at the orphanage.
- Everyone Calls Him "Barkeep": All non-hostile people refer to the skeleton soldier as Sir Knight.
- Exact Words: Skeleton soldier is given a flamethrower that shoots unquenchable flames and a fire retardant powder that will keep him from feeling the heat. He uses the flamethrower, torches a bunch of thugs and spiders and promptly melts unaware that he was in any danger. He couldn't feel the heat.
- Failure Knight: It's right there in the title. The first thing that ever happened to the skeleton soldier was he failed to protect the necromancer who raised him; apparently the next twenty years weren't much better, and he died failing to protect his succubus queen.
- Fantastic Racism: Everyone attacks the skeleton soldier on sight, which is probably understandable since normal skeletons are mindlessly aggressive. But even when they find out that he can talk and he politely asks them to leave him alone, they still attack.
- Feel No Pain: The skeleton soldier and Rena are given a powder that will keep the from feeling the heat of a magical fire they'll use to wipe out a cave of spider monsters. As a result of using it, the skeleton soldier doesn't realize it's harming him until his body melts.
- Foreshadowing: In her introductory chapter, Rena claims to have no problems working with the skeleton soldier because she hates humans. It's later revealed she was raised at an orphanage run by a slime monster.
- The Many Deaths of You: The skeleton soldier has died many, many times, usually to adventurers.
- Monster Is a Mommy: The spider cave's boss is a spider queen that reacts viciously to its spawn or eggs being threatened. While she and her children eat people, the story is not unsympathetic: It's very clear that her children are hostages, that she cares for them deeply and isn't particularly malicious or anything.
- No Name Given: The skeleton soldier.
- Out of Continues: Skeleton soldier is not sure how many times he can resurrect, and isn't interested in testing it. The only hint that he may run out is that when he dies his assimilation rate goes down. What happens at 0% is unclear.
- Reality Ensues: The skeleton soldier and a rogue set up shop in a low-level dungeon, killing assassination targets that the rogue brings to him. The nearest city soon sends a band of high-level knights to find out what is causing trouble.
- Revenge Before Reason: At times, the skeleton soldier's desire for revenge against those who wronged him (usually by killing a companion), causes him to lose sight of everything else, always resulting in his death. One death is caused by him going wild with a powerful weapon and, it's implied, accidentally killing the woman he was trying to protect along with himself.
- RPG-Mechanics Verse: It's implied that everyone can level up, but the skeleton soldier is the only one with actual menu screens and system alerts.
- Save Scumming: The skeleton soldier doesn't just resurrect on death, he goes back in time with all his memories and experience intact. This lets him grind for experience a bit on the mercenaries who ordinarily would have been far outside his ability to defeat.
- Stat Grinding: The skeleton soldier can increase skills by using them, but he learns simply practicing over and over can become difficult. Grinding his swordsman ability requires he swing his sword exactly right every single time or it doesn't count, so he can't simply zone out as he practices.
- Taught by Experience: Besides actually leveling up, the skeleton soldier does better each time he resurrects because he knows what tricks his enemies will use.
- Tournament Arc: Chapter 23 begins a tournament the skeleton knight is hired to enter by Rubia's uncle.
- Town with a Dark Secret: A town the skeleton knight and Rubia visit is filled with opium addicts and the noble running it is breeding spider monsters in a nearby dungeon.
- Unreliable Expositor: Whatever is responsible for telling Skeleton Warrior about his level ups and available quests refers to Rena as a backstabber that will turn on him the moment he's vulnerable, but she rather quickly falls in love with him and repeatedly throws herself into mortal danger (and possibly mortal wounds) to save him even when it would be far safer to flee and she has nothing to gain by staying.