Haven scouted by Tau

With the realisation that the Rifts of Hecate contained several threats, and the growing awareness of the possibility of the Hecate Gap being a strategically vital pathway to transit between the Rifts and the Hadron Expanse, in 10.022M42 the Tau made the decision to redirect their forces towards controlling the Gap. Initially this meant sending small scouting forces to both Ergura's Fall and Haven to establish the strength of other forces in the vicinity.

Stealth teams and pathfinders were sent to Haven to pave the way for a full Tau invasion, but while their forces had some success at Ergura's Fall, the results on Haven were extremely discouraging. One stealth team was ambushed by an eldar force without warning, which came as a surprise to the Tau who considered the eldar occasional allies. There was no attempt to parley, and although the eldars' aggressive attack led to initial heavy casualties, the eldar managed to secure vital objectives by sneaking through the Tau overlapping fields of fire. Unable to progress in that direction the Tau withdrew.

Meanwhile, another Tau fire team found itself receiving unwanted attention from the Sky Lords chapter of space marines. The Sky Lords were not on Haven in force, but the superhuman strength of the astartes forced the Tau to withdraw once again. Later, an Angels of Vengeance squad encountered and defeated yet another Tau scout unit, and it became clear to the Tau that Haven was already being probed by significant forces from other factions.