This card singlehandedly makes Ceremonial Sickle and to a much lesser extent its upgrade not absolutely terrible. The problem with the sickle is the secondary attack having no bonus to hit, requiring some expenditure of resources into an already expensive card to deal a single point of damage. But with the mask, because you're going to be clearing and re-applying doom constantly, you'll have no shortage of +2s to help overcome the missing attack bonus.

This comboes extremely well with Blood Pact and Sin-Eater. It is 9 xp, but for that you get pretty much inexhaustible Guts/Overpower on demand:

• 2 charges to start with
• recharge the mask with one use of Blood Pact (and gain +3 from there)
• after the mask is again empty, move the doom to Sin-Eater, the mask refills again. You do have to occasionally use an action to empty the doom (and while there is doom in there, moving another doom doesn't fill the mask), but it's extremely action and resource efficient.

Obviously, this card makes the doom charm suite much better Dowsing Rod, Ceremonial Sickle, Onyx Pentacle, Hallowed Chalice, especially at level 0. Something you might not have noticed is that the mask also recharges when the first doom is placed on the agenda, an enemy, a treachery, etc, which makes it possible to take this mask for its skill values without the doom suite in those campaigns that really like doom.