The Staff of Ice in *Call of Duty: Black Ops 6* Zombies is a unique Wonder Weapon; its base form is underwhelming, but its upgraded version, Ull's Arrow, is crucial for high-round survival and Easter egg completion. Here's how to upgrade it.
Prerequisites for Upgrading the Staff of Ice
Before upgrading, you need the Staff of Ice itself. Obtain it from the Mystery Box or by collecting its three parts. Access to the Dark Aether Nexus, opened via the Door to Nowhere, is also essential for the upgrade quest.
How To Upgrade the Staff of Ice
Step 1: Freezing Dark Aether Crystals

Freeze three Dark Aether Crystals rapidly using the Staff of Ice. These crystals are found in underground lanterns (black frame, purple fire). Perks like Stamin-Up and PHD Flopper (with Tribologist) significantly improve your speed for this step. Optimize your route; starting in the tomb area, then the Shrine of the Hierophants, and finally the Subterranean Temple entrance lantern is usually fastest. Archibald will comment upon success; then, proceed to the Dark Aether Nexus.
Step 2: Floating Rocks in the Dark Aether Nexus

Three floating rocks with glowing purple runes appear in the Dark Aether Nexus. Shoot each rune with the Staff of Ice (you'll get a hitmarker). This lowers the rocks, making the runes easier to target. A scoped weapon might help. The order doesn't matter; shoot all three.
Step 3: Rune Symbols Puzzle

A portal back to the main map will be replaced by a stone wall displaying runic symbols. Three match the symbols from the floating rocks. Shoot these with the Staff of Ice. The portal will open (even if you're incorrect, but incorrect choices lead to a less favorable respawn location). If correct, you'll find yourself on a floating rock with a purple orb. Interact with it.
Step 4: Soul Chest Orb Escort

The orb will move; kill zombies near it to power its movement (a purple trail indicates this). It will eventually settle in a central structure, forming a small purple portal. Interact to upgrade the Staff of Ice to Ull's Arrow.
Ull's Arrow: Upgraded Staff of Ice
Ull's Arrow boasts a powerful charged attack with high AoE damage and an alternate fire for reviving downed players, similar to its Origins counterpart.
Call of Duty: Black Ops 6 is available now on PlayStation, Xbox, and PC.