Reaping Blow (X) "If a Model with this Special Rule is outnumbered, it gains extra attacks."
If a Model is outnumbered in Combat and either has this Special Rule or is made to attack with a Weapon that has this Special Rule, then that Model gains a bonus to its Attacks Characteristic equal to the value of X attached to the variant of this Special Rule it has access to. To be considered outnumbered, the total number of friendly Models Locked in Combat in the same Combat must be less than the total number of enemy Models Locked in Combat in the same Combat - Models with the Bulky (X) Special Rule count as a number of Models equal to the value of X in the Variant of the Bulky (X) Special Rule that Model has. This Special Rule has no effect during the Challenge Sub-Phase, and no Model that is Engaged in a Challenge may gain additional Attacks due to this Special Rule.