Hive Fleet Poseidon makes gains

In early 10.023M42 the real extent of the threat posed by the tyranids in the Rifts of Hecate began to dawn on several factions active in the Hadron Expanse. For several months the Tau had been fending off repeated tyranid incursions on Garmenes assuming that the hive mind didn't have any real plan and was acting on instinct. However, as the latest force of tyranids arrived on the world, it became abundantly clear to the Tau that hive fleet Poseidon had been repeatedly testing the defences of Garmenes to work out what combination of force they would need to establish a bridgehead.

On 0810.023M42 the hive fleet did just that, by landing further tyranid creatures on Garmenes by spore, indicating that somewhere in the system there must be lurking hive ships. The Tau launched a pre-emptive strike against the landing tyranids, and successfully eliminated their large synapse beasts in the opening moments of the engagement. However, they were unable to stop wave after wave of smaller gaunts from overwhelming the Tau positions, and were hampered by opportunistic hit and run attacks from independent tyranid units in their rear areas. Despite maintaining good discipline and inflicting punishing losses, the Tau were unable to hold onto their positions, and withdrew, allowing the tyranids to finally gain a foothold on Garmenes.

Elsewhere the Aeldari on Lodax faced the sudden appearance of a genestealer cult, believed to be associated with Poseidon on Lodax. This caught the eldar by surprise, and destabilised their position on the secondary world, causing a general withdrawal of Aeldari forces from the world. At roughly the same time, they aliens of the hive mind deliberately delved into ancient necron tombs on the world, waking the necrons and causing a retaliatory strike from the necrons of an unknown dynasty. This appeared to be what the hive mind intended, as the necrons were defeated then forced to abandon their tombs. With the necrons removed and the Aeldari having retreated, the tyranids wasted no time in consuming the world of Lodax II and converting it to useable resources.

With Lodax II, Candic Minor and Mezria IV now absorbed by hive fleet Poseidon, even the imperium now realised that the threat from this new hive fleet was serious. Discussions immediately turned to the defence of Ergura's fall, as the loss of the gateway to the Hecate Gap would doom the imperial operation in the rifts, and might threaten the wider Hadron Expanse.