Overview
Piscina IV is a garrison world remembered for the ork invasion its defenders and the Dark Angels threw back at brutal cost.
Its watch-keeps and basilica-forts assume the greenskins will return, because they always do.
Beyond the Rift, that assumption is now policy.
M41 and M42 status
Garrison world scarred by ork invasion.
Nihilus-side garrison holding against renewed raids.
Timeline
Ork forces under Ghazghkull and Nazdreg assault Piscina IV — a live test of the WAAAGH! on the eve of the Third War for Armageddon.
Dark Angels intervention under Belial breaks the invasion at the Basilica.
Rift isolation leaves the garrison reliant on local musters.
Renewed raid warnings keep the watch-keeps at full readiness.
Cartographic positions and several administrative details are intentionally approximate where published Warhammer sources conflict or provide no canonical coordinate system.