Boltarean secured by Tau

While the focus of the main factions in the Hadron Expanse remained fixed on events in the Rifts of Hecate, the tau had only deployed three of their five recently arrived Hunter Cadres to the Rifts. The remainder they now consolidated under the tau commander Malkaor, and took advantage of the focus elsewhere to pursue their main agenda, the Hadron Expansion Sphere. 

Having built up a significant force and colonised a number of systems alread, they now turned to finishing off the war at Boltarean. Striking without warning the tau used their logistical advantage to overwhelm the defences of Boltar Prime, and despite the intervention of the Thousand Sons, the fall of the world took less than a day. For some time the tau were worried that the daemonworld "Fecus Major" would intervene to help, but this did not happen. Instead the daemonworld and its attendant fleets simply vanished from the system. If the forces of Nurgle had an agenda in the Hadron Expanse it did not appear to include helping the Emerald Serpent.

Having secured Boltarean the next target was clear. The imperial system of Palantir, and from there, the rest of the Hadron Expanse would be added to the Tau empire.