At the end of any phase in which the Master is removed as a casualty, every unit in the Army with one or more models with Ashes to Ashes must pass a Discipline Test or lose a number of Health Points equal to the amount by which the test was failed, with no saves of any kind allowed. These Health Point losses are distributed following the rules for Unstable, except that they can never be distributed to models that do not have Ashes to Ashes. The number of Health Points lost is reduced by 1 if the unit receives Rally Around the Flag.
At the end of the Player Turn in which the Master was removed as a casualty, a new Master may be selected. To do so, nominate a friendly Wizard Character, which either has Vampiric or is using Evocation. This Character becomes the new Master.
At the start of each friendly Player Turn after the Master has been removed as a casualty and no new Master has been selected, every unit with Ashes to Ashes must once again pass a Discipline Test or lose Health Points as described above.