Dark priest, Common, 3g
Demonic. Undead.
Wall -7
Discards all Purified ashes from your hand.
I'll be honest, I don't see why someone would take this into their deck rather than
Purified fire for only 1 gem. The only benefit here is that it has the keywords, so having it on hand passively aids an Undead deck even if it's never played... though that's a double-edged sword as it can be one of the cards replaced by Purified ashes. I guess that adding this to the card pool means it could be summoned via its keyword, so it could come into play that way, but I'd prefer to see it stand on its own to be worth choosing.
That's looking at it from the perspective of being a safeguard against having Purified ashes placed into your hand. As a general-use card, it's useless. When there are no Purified ashes in play, all it does is reduce your own wall by 7, reduce your own tower by 2 (Demonic effect), and possibly return 2 gems if you were to waste an Undead trigger on it.
Was this supposed to have some effect on the opponent? Was the "Wall -7" supposed to be enemy wall? That would cast this in an entirely different light.