aside from the fact that 3 card strategy could fall on its face in the face of bleed and burn (which do max hp based damage) once the higher level opponents are no longer stuck starting with their base hp not a bad strat honestly.
Lambs to the Slaughter and Path of Worship cards boost your HP to high heavens (through Dominant and Empowered buffs), so you can just pop in Blood Pact and instakill whoever, even with the bugged starting HP (as some have access to MAD healing).
Why I probably dismissed Lambs to the Slaughter and Path of Worship in my post, is because those two are both in Succubus deck AND "Remove on use" cards.
And yes, I noticed the maxHP% damage only after fighting Valeria. :|