If the guardians of a Casket of Souls are slain, the tortured souls contained within the vessel will escape their confines in a raging maelstrom of destruction and vengeance.
If the crew of a Casket of Souls is reduced to zero Wounds, immediately roll a D6 for every unit (friend or foe) within 12" of the model. On a roll of 4+, the unit suffers D6 Strength 3 hits, with no armour or Regeneration saves permitted (Ward saves can be attempted as normal). Once these hits are resolved, the Casket of Souls is removed from play.