So I was looking at the duelist upgrade card and something caught my attention. Duelist states that you gain Immune: Pierce. Mandos already have Impervious. Does this mean that Mandos would gain extra defense dice from impervious while still being immune from pierce, effectively granting bonus defense vs. anything with pierce? Does the pierce keyword stay in the attack pool even if "pierce cannot be used against you" or does the impervious not trigger because pierce is removed from the pool as it "cannot be used..."?

1 minute ago, Varulfr said:

So I was looking at the duelist upgrade card and something caught my attention. Duelist states that you gain Immune: Pierce. Mandos already have Impervious. Does this mean that Mandos would gain extra defense dice from impervious while still being immune from pierce, effectively granting bonus defense vs. anything with pierce? Does the pierce keyword stay in the attack pool even if "pierce cannot be used against you" or does the impervious not trigger because pierce is removed from the pool as it "cannot be used..."?

If you have Immune Pierce you do not benefit from Impervious.

Page 49 of the RRG, last bullet point of Impervious:

If a unit has both the impervious keyword and the immune: pierce keyword, the impervious keyword has no effect because pierce x is not being used during that attack.