Grixis token sac attack! Bring the pain with Impact Tremors, token generators, and our new friend Essence Flux.
Essence Flux
+
Priest of the Blood Rite
is particularly good. When you drop the priest, your opponent focuses fire on the 5/5 flier. Flux the priest and you've got another demon, at instant speed, for one blue mana.
Faerie Miscreant
+
Mirror Mockery
gives you a Thieving Magpie on turn 2.
Mirror Mockery
+
Whirler Rogue
: Attack with the Rogue, then tap the two Thopters his token drops to make the nontoken one unblockable.
Stack a couple of Mirror Mockery on a Fleshbag Marauder to sweep their board every time you swing. (You just sac the tokens to their own ETB trigger.)
My theory about Essence Flux? People overlook it because of the Spirit bonus and the lack of good Spirits to use it with. Sure it's decent in Spirit tribal, but it's bonkers in here.
Thopters add up fast when you Flux a Whirler Rogue or Chandra's Mom and Dad. With even one of your Impact Tremors on the board, that's a lot of pain.
Get maximum value out of Fleshbag Marauder: Respond to his ETB trigger with Essence Flux and/or Altar's Reap or Fiery Conclusion.
On a budget? Replace Sunken Hollow with Submerged Boneyard and Smoldering Marsh with Cinder Barrens, and some basics to keep your speed up.
When your opponent brings in token hate like Virulent Plague and Flaying Tendrils, you've got a nasty surprise: Runaway Carriage! How has nobody discovered this card? A four-cost 5/6 trample that you can copy with Flameshadow Conjuring and/or preserve with Essence Flux. (Cast the flux in response to his sacrifice trigger at end of combat.)
If your opponent is running a slower deck, you can bring in Flameshadow Conjuring for amazing creature generation. Flux something and Flameshadow it to get two ETB triggers for one red and one blue mana.
