Phantine

Phantine is a Sabbat Worlds gas-and-spire planet, the Gaunt's Ghosts airborne war where Ouranberg and the Phantine Air Corps shared a sky full of toxins. This pin sits in its own system on the Pacificus/Tempestus smear the crusade never drew cleanly.

The Ghosts learned to fight up. Chem-weather, hive-spires punching through cloud, and a planetary specialism in air war are why Dan Abnett kept coming back. Phantine is not Tanith, not Verghast, and not a random gas giant with no Guard regiment.

Phantine still matters as the Sabbat airborne world. Unofficial summaries keep the phantine-system parent and refuse to relocate the pin wholly into Pacificus or Tempestus against the map's mashed Sabbat placement.