The Celestial Katana in Pilgrammed appears to be a mix-up with the Nagakiba , which the wiki lists as a mid-game melee weapon dropped by King Sandpod.

How to get it

  • Find and defeat King Sandpod.
  • The weapon drops from that boss, so the main requirement is farming the boss until it appears.
  • If you were actually looking for a celestial item, the game also has the Celestial Ring , which is dropped by Eye Flies.

Quick note

A lot of forum and video results seem to mix up weapon names, so “celestial katana” may be a community shorthand rather than the exact wiki name.

Source-backed scoop

The Nagakiba is a mid-game melee weapon dropped from King Sandpod.

TL;DR: Beat King Sandpod to get the katana-style weapon people usually mean in Pilgrammed.