While a friendly trooper unit at 
and in LOS of a unit that has the Guardian X keyword is defending against a ranged attack, it may cancel up to X hit 
results during the Modify Attack Dice step of the attack sequence. For each hit result canceled in this way, the unit with the Guardian X keyword rolls a defense die matching the one on its Unit Card. After converting any defense surge 
results according to its surge chart or by using surge tokens, the unit with the Guardian X keyword suffers one wound for each blank result. A defending unit that has the Guardian X keyword used on it gains a suppression token as normal.A unit cannot use Guardian X if the defending unit also has the Guardian X keyword. If multiple friendly units can use the Guardian X keyword during an attack, the player who controls those units declares which unit is using the Guardian X keyword and resolves their ability before choosing whether to declare that another unit is using the Guardian X keyword.A unit cannot use Guardian X if it has a number of suppression tokens equal to or greater than its courage.The Pierce X keyword can be used to cancel block 
results on defense dice rolled by a unit using Guardian X; treat canceled block results as blank results. After using Pierce X in this way, any unused Pierce X value can still be used to cancel block results rolled by the defending unit.Additionally, a unit with the Guardian X keyword cannot benefit from backup and ignores the 
rank requirement to provide backup.