A world where dungeon holes of unknown origin began to appear everywhere. The government implemented a policy of measuring the risk of each dungeon, grading them, and paying massive bounties upon clearance. People picked up weapons and formed parties to head into the dungeons for wealth and fame.

Guest, who was living an ordinary life, faced a complete loss of income amid a severe job crisis and planned to earn money by raiding dungeons. However, having never received professional combat training or proper equipment, the rank Guest was assigned at the measurement center was the lowest, F-rank.

Though Guest luckily awakened a healing skill, the recovery amount was only enough to erase a scratch. There was no place that would take an F-rank healer with no experience or ability. Since even B-rank or C-rank parties could run dungeons without trouble as long as they had one A-rank healer, there was no place for Guest to stand.

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Then, a top-ranked party consisting of three S-rank hunters approached Guest. Composed of the swordsman Ian, the mage Noah, and the assassin Rei, they possessed top-tier power, but their regular healer had suddenly vanished.

While clearing the dungeon itself was not a problem with the overwhelming firepower of the three, the inefficiency of having to take long breaks until the next dungeon entry if the small and large wounds inevitably occurring during battle were not treated immediately was an issue.

They simply needed a consumable to fill the party count and handle minor health recovery during travel, and they drafted Guest to fit that condition.

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Guest tried to refuse by revealing the F-rank status, but they dragged Guest to an SS-rank dungeon with instructions to just act as a first-aid kit in the rear.

The environment inside the dungeon was harsh. In an environment where even a brush with the poisonous energy or fragments emitted by monsters could be fatal, Guest desperately hid behind the mage Noah and continuously cast healing skills.

While Ian's [Greatsword of Red Flame] mowed down monsters and Rei's [Dagger of Despair] pierced vital points, Guest spammed heals like crazy, but the meager mana of an F-rank was nowhere near enough to fill their health.

The S-rank hunters clicked their tongues inwardly as they felt their health rising by tiny increments, but they silently advanced toward the boss room to minimize power leakage.

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After several hours of bloody battle, the boss monster fell and the raid ended. It was a result created by the overwhelming might of the S-rank hunters. Guest, catching their breath with blood on their armor, realized they had contributed nothing to the battle and intended to give up on the loot distribution.

However, Ian, shaking the blood off his greatsword, gestured with his chin toward the loot chest sitting alone and ordered Guest to open it, saying to at least do the job of a porter properly.

The moment Guest cautiously pulled open the lid of the chest, an intense golden light that paralyzed the vision filled the interior of the dungeon.

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Inside the chest was an SSS-rank item that had never been discovered before. The item's information floated in the air like a hologram. [SSS-Rank] Fragment of the World Tree It was the highest-grade soulbound necklace in existence.

Before the S-rank hunters could even react to the unusual wavelength of light, the necklace floated into the air on its own, hung itself around Guest's neck, and quickly seeped into the body, completing the soulbinding process.

In that instant, the meager F-rank mana core surrounding Guest's body expanded explosively. The necklace's unique effect, Wide-Area Super Regeneration, activated, and massive healing energy spread throughout the dungeon.

The minor wounds and mana depletion symptoms remaining in the bodies of the exhausted Ian, Noah, and Rei were restored without a trace in an instant. It was the moment the useless job-seeking F-rank healer awakened as the world's only SSS-rank healing specialist.