Oreparts

Oreparts (オーパーツ, from the real-world term "OOPArt" — out-of-place artifact) are a class of extraordinary items found chiefly as dungeon treasure in the world of That's My Dungeon My Life. The protagonist Wof, who carries memories of a previous life, recognizes the name from Earth legends such as the crystal skull, the golden "shuttle" ornament and the dinosaur figurines — objects supposedly too advanced for their era. In this world the meaning is different: an oreparts is a medium that amplifies the power of a Relic. They usually take the form of weapons, armor or accessories, are exceedingly rare, and can command enormous prices.

The defining trait of an oreparts is compatibility. An item only functions as an oreparts if it can adapt to (適応) a specific Relic; the Relic's owner is said to sense that affinity, as though drawn together by fate or chosen by the object. When adapted, the oreparts boosts the Relic's effect and its own durability increases; when not adapted, it is nothing more than an ordinary weapon or trinket. Because true compatibility is so hard to find, discovering a well-matched oreparts is regarded as a mix of luck and skill, and stacking or overlaying effects is possible only through an oreparts.

Oreparts sit within a broader hierarchy of dungeon spoils — Legacies (consumable magic-like items), Legendaries (permanent versions) and Relics themselves. Their status is such that anything "nation-shaking" involving Relics, oreparts or Legendaries is treated as a classified matter, and finding one earns a special discovery bonus at the explorers' guild. A rarer subclass are "soul-dwelling" oreparts — legendary pieces said to be held by unnamed Rank I explorers. Notably, monsters are even more suited to Relics and oreparts than the human races: a beast wielding a compatible oreparts, such as the wind-Relic hobgoblin whose saber was an oreparts, becomes dangerous on an entirely different level even to high-ranked explorers.

Oreparts thread through the story as objects of value and danger. The antique dealer Alifa, using her Relic [Appraisal], first identifies a set of rings Wof unearths as oreparts and refuses to buy them outright, sending them to the guild instead. Named examples include the Pleiades Blade tied to Riv, a spear carried by Mineha, and the Vanish Knife — an oreparts adapted to the [Vanish] Relic that erases whatever it cuts — which Wof specifically seeks out for himself.