Elixir

Elixir is a Legendary-class treasure (レジェンダリー) described as the "medicine of life and soul" and the "panacea of the divine age" — a mystical water that heals any wound and can pull even the dying back from death when nothing else, not Potions nor the [Healing] Relic, can reach them. It is the rarest of the rare, a "drinkable Legendary" whose value is beyond reckoning; merely revealing its existence is thought capable of driving men to kill and even sparking wars, so the state treats any matter involving it as a classified secret. In the world's lore, the sole known source was a sacred egg (神聖卵) sealed in the innermost chamber of a ruined temple atop a frozen, monster-infested mountain — a nigh-impossible prize that a legendary near-first-class explorer once obtained at the cost of a month bedridden, and which has since been confirmed depleted.

The protagonist Wof unearths a genuine Elixir in Chapter 6 while digging through the Junkyard, drawn to it as a blue-lit "Super Ultra Rare." It comes sealed in an exquisitely lifelike, egg-shaped vessel inscribed in gold with the ancient word "Elixir." Recognizing from his past-life memories exactly what it is and how dangerous it is to possess, Wof cannot sell or show it to anyone. He soon spends it entirely, without hesitation, to save three near-dead members of the third-class explorer party Trquetum whom he finds bleeding out — an act driven by a doctor's conscience from his previous life rather than any hope of reward, and by his own wish to be rid of so perilous a thing.

The egg-shaped vessel proves to be far more than a container: it is itself a Legendary Relic that spontaneously regenerates the Elixir from nothing, refilling completely in roughly ten minutes — an "infinitely welling" supply that Wof recognizes as terrifyingly powerful and keeps hidden deep in his pouch. This turns an ordinary one-use miracle into an unlimited resource. Poured onto a blade, the Elixir transforms it into the radiant, anti-undead "Holy Edge" that one-shots any skeleton and cleaves through even a Relic knife like melting butter; it also erases fatigue and can reattach severed limbs.

The Elixir becomes a quiet linchpin of the early plot. The revived Trquetum members — leader Lupinus, cat-beastwoman Pakira, and the uncanny swordswoman Riv — investigate who healed them for free, an act so unthinkable it must have been someone with a hidden agenda. Riv's abnormal sense of smell lets her track the Elixir's lingering "scent," and from it Pakira deduces that its user must be a hired-child (雇い仔) permitted to witness so precious a Legendary in use — clues that begin to draw the group back toward Wof and mark him, in their eyes, as "the Elixir boy."