From Dragon Quest Wiki
The infinity trousers are a piece of legwear in Dragon Quest IX. They are the most protective pair of pants in the game and the only with a five-star rarity ranking. They can only be created if an Alchemiracle is performed.
|Infinity trousers (DS)
|Super-steady slacks that stand up to all sorts of strangeness.
|Increases resistance against sleep, paralysis, dazzle, and instant death effects.
Recipe: Immortal trousers + Agate of evolution x3 + Purple orb x3
Can only be crafted when an Alchemiracle is performed.