Anubis's Wrath is an Artifact Iron Sword of Anubis. It is the only artifact of Anubis, and Anubis is the only god in Atum's pantheon to have a single artifact. Like all artifacts, it can be obtained from Pharaohs in Pyramids, breaking a Godforged Block (Unaligned or of the god), and extremely rarely from crates and Relic Ore.
Soul Drinker: Absorbs the souls of slain foes, growing stronger.
Anubis' Wrath requires progressively more kills to reach higher tiers, with an increase of 1 damage and .1 attack speed per tier, up to tier 3. 50 kills are required to reach the 1st tier, 70 (120 total) to reach the 2nd tier, and (untested, only gauging based on progress bar) ~300 kills to reach the third tier, after which it (should) be slightly stronger than Netherite, at 9 damage.
Note: If you happen to die while carrying this item, it will lose half of its total kills. Requiring you to fill up the progress bar again.