Hearthpwn

2 Step achievement, put in Runed Mithril Rod to help with reduction.

Nofin's Imp-ossible card requires you to have both copies, because the achievement is to cast the deathrattle, on other imps

I was able to do the first round with just 2, but second does need 4. So with reduction combo to one time it would be:

Either Fiendish Circle or a 4 casting Wicked Shipment

Cast first Nofin's Imp-ossible on 4 imps

Hellfire to destroy them, then second Nofin's Imp-ossible for the achievement.

You can also if you have 4 or more imps already on board and can kill them off, cast that way

Good luck - was able to complete in 2 games