Slayers are bitter fighters who seek their doom in battle, yet so fierce is their pride and so sacred are the vows of the Slayer Cult that they are incapable of acceptingtheir fate graciously. Upon their death, a Slayer will use their final breath to strike at the foe.
When a model with this special rule is reduced to zero Wounds by an enemy attack during the Combat phase, the unit that made the attack suffers a Strength 3 hit, with an AP of -1.
Note that if this model is reduced to zero Wounds whilst engaged in a challenge, it is the model that made the attack that suffers this hit, rather than its unit