Piscina

Piscina is a leftover Segmentum Obscurus neighbourhood pin for the Dark Angels mining well already researched as Piscina System, not a parent of Piscina IV. This existing row has no children; IV and V already live under piscina-system.

The real story sits on those numbered worlds: IV is the mine-head Ghazghkull used before Armageddon, where Chaplain Boreas died rather than virus-bomb the planet, and V is the volcanic recruiting rock. This pin is the un-numbered cube some maps drop six thousand light years east of the Eye.

Piscina still matters as a neighbourhood leftover, not a fourth Dark Angels world. Unofficial summaries keep the Obscurus parent, refuse to steal IV's garrison dossier, and do not re-parent the researched children onto this row.