This particular The Demon Seed deck revolves around fatigue damage being redirected to your opponent through the likes of Hand of Gul'dan and Backfire, with the former benefiting greatly from the inclusion of Tamsin Roame.  

It should be noted that Nightshade Matron may sometimes erroneously discard either of the two Flesh Giants if you have been unable to sufficiently reduce their cost, however, the enormous upside they afford does (imo) negate this. In addition to this, the interaction between Mo'arg Artificer and Unstable Shadow Blast does not resolve as you might otherwise expect; you simply take the excess damage as if Mo'arg Artificer wasn't present (although you still deal the full twelve damage).