What the game says, what really changes when you play, and the code to unlock it. Steam says 31.8% of players have it.

Artifact of Command
Game text: «Choose your items.»
Every chest, printer or boss drops an essence of its rarity; pick it up and choose any item of that rarity. Printers and the Shrine of Order still work as usual. Lunar and equipment items can be chosen too.
For learning what each item does, testing combos and the challenges that ask for specific items. It makes the run much easier: do not count it as a real clear.
It is in the base game. 31.8% of all Risk of Rain 2 players on Steam have it, from Steam's public stats on 31 October 2026.
Read top to bottom, as shown here: three rows of three shapes. Each slot on the generator changes shape when pressed, in this order: square ■, circle ●, triangle ▲, diamond ♦.
In co-op, the group can enable any artifact that any player has unlocked. Artifacts are chosen in the menu before the run starts.
Enter its code (■■■ / ■■■ / ▲▲▲) in the Compound Generator on Sky Meadow or Helminth Hatchery, use the laptop and beat the Bulwark's Ambry trial: take the key and break the reliquary.
Every chest, printer or boss drops an essence of its rarity; pick it up and choose any item of that rarity. Printers and the Shrine of Order still work as usual. Lunar and equipment items can be chosen too. For learning what each item does, testing combos and the challenges that ask for specific items. It makes the run much easier: do not count it as a real clear.
31.8% of all Risk of Rain 2 players on Steam have it, from Steam's public stats on 31 October 2026.
Sources: the game's English text (artifact name and description), the Risk of Rain 2 wiki (riskofrain2.wiki.gg: the Artifacts page and this artifact's page, read on 31 October 2026; code, Compound Generator and Bulwark's Ambry) and public Steam stats. The plain-words text is ours. Icons: Risk of Rain 2 (Hopoo Games / Gearbox).