I know that Shields can be used to block against Pierce attacks, but can shields block against attacks that 'ignore armor'?

Wanderer999 said:

Unless it is specified, then no. Iron Shield, Crystal Shield, Shield of Light and Mirror Shield (I think that is its name) all say they can't be used to cancel wounds from effects that ignore armor.

Skull Shield is the only one (as far as I know) that allows you to cancel wounds fro effects that ignore armor.

It's been a while since I've actually looked at a shield card, do they have an Armor keyword on them? Or just "Shield?"

Regardless, I agree with Remy.

Their item type is listed as "Shield".

Remy's conclusion is right, but the reasoning is actually backwards. By default, there's nothing preventing shields from "blocking" attacks that ignore armor. However, most shields specifically add that restriction on the card.

EDIT: This is similar to runes/armor. Many armors cannot be used with runes, but there's no general rule stating that wearing armor prevents you from equipping runes, so the default is to allow it.