They Killed the Father!
(Rule)Description: If the Magus and Patriarch are both killed, at the moment the last has died all Brood Brother units and Hybrid Broods must take a Morale test with the following modifiers: -1 if the unit is < 50% starting strength and -1 if the unit is pinned or falling back. If this test is passed, the unit is Fearless for the rest of the game. If it failed, the unit will Fall Back immediately, though they can regroup in later turns as normal.
If the unit was in combat when this Fall Back move occurs, the enemy unit may only Consolidate.