The Ar'kringa of the Alliance, small kobold like beings, use the sundering and the confusion to begin the deployment of various experimental biological agents either directly onto Imperial worlds or indirectly via agents (Ulnus) or via unwitting plague ships who've unknowingly carried their lethal cargo for sometime. Among these are several new variants of Maculovirus caeruleus (Cerulean Pox) engineered with a first and second generation long latency, it's carriers oblivious as they shed virus among the displaced and the fleeing. The massive epidemic is only realized some three months into the conflict as the first widespread wave of cases begins.