The Ordo Xenos declares its prey, slips into a xeno-infested ruin, and burns the nest out root and brood before it can breed or reanimate. This is the hunt the warband was built for — the adaptive strike against a single alien breed, not a brawl against a foe of no fixed type.
ATTACKER AND DEFENDER The attacker is the Ordo Xenos, prey declared, come to clear the nest. The defender is the xeno infestation — a nest of the declared breed racing to complete its breeding or reanimation cycle before it is purged.
BATTLEFIELD A dense, infested ruin, with three nest-markers set across it and the brood gathered around them.
DEPLOYMENT The defender places the three nest-markers and deploys its brood around them. The Ordo Xenos declares its prey and deploys second on the facing edge, and may place up to two fighters in hidden deployment by Hunters Unseen.
OBJECTIVE The Xenos must clear the nest — destroy all three nest-markers and take the priority alien Out of Action — before the brood completes its cycle of three uninterrupted activations on the markers, or grinds the thin retinue below its native majority.
ENDING THE BATTLE AND VICTORY The Ordo Xenos wins by clearing all three nest-markers and downing the priority alien before the cycle completes. The infestation wins by completing its cycle, or by breaking the retinue below its native majority first.
REWARDS The winner gains Reputation. The Xenos additionally banks a favour roll if it cleared the nest without losing a single native Throne Agent, and a cleared nest deepens its special-issue pool, as told in The Accumulating Armoury.
CONTROL TRACK A Xenos clearance-win advances its control-track claim by one step and marks the world purged of the breed. An infestation win holds the claim and leaves a surviving brood that re-seeds the ruin on that world's next battle.