What Are Artifacts in Genshin Impact: the 5 Slots, Main/Substats & How Upgrading Works

The Flower and Plume have nothing to choose — they always come out as HP/ATK; only the other 3 slots need "hunting" for the right main stat, and for every set, the correct main stat always matters more than the set bonus or perfect substats.

There are roughly 62 artifact sets in the whole game (as of 6.7/Luna VIII), and each Domain of Blessing drops 2 different sets. Every set has two effect tiers: wearing 2 of 4 pieces from the same set unlocks the 2-piece bonus (usually a flat % stat boost), while wearing all 4 of 4 unlocks a stronger 4-piece bonus (usually with its own trigger condition). You don't have to run a full 4-piece set: mixing 2+2 (2 pieces from Set A + 2 from Set B) is often stronger than forcing a 4-piece set built from weak-substat pieces; a "4+1" setup (4 pieces of the main set plus 1 loose piece purely for the right main stat) is also a valid choice when the fifth slot won't roll right in the main set.

Every artifact piece upgrades using Mora + spare artifacts as fodder, going from +0 up to +20 for a 5-star piece (lower rarities cap lower). Every 4 levels of upgrade grants one substat roll (adding value to an existing substat, or unlocking a new one if the piece doesn't have 4 yet) — a fully upgraded 5-star piece gets several substat rolls depending on how many it started with. Each roll's value is NOT fixed — it lands on one of 4 roll tiers we've confirmed straight from the game's own data files (not a community estimate) — for example, a CRIT Rate substat roll lands somewhere between roughly 2.72% and 3.89% depending on the tier, not one single fixed number.