Black-red sacrifice is really fun and evil.

I use:

2x Grim Initiate
4x Footlight Fiend
4x Orzhov Enforcer
3x Priest of Forgotten Gods
4x [c]Dreadhorde Butcher[/b]
3x [c]Heartfire[/c]
4x Mask of Immolation
3x Midnight Reaper
3x Judith the Scourge Diva
4x Mayhem Devil
2x Chandra, Acolyte of Flame
2x God-Eternal Bontu

8x Swamp
7x Mountain
4x Blood Crypt
3x Dragonskull Summit

The duals may not matter just because of the Treasures. You can cut Bontu; she is too slow. You just open with a Dreadhorde Butcher, then start swinging away. Once you have Mayhem Devil, if they can't kill it immediately, you just start burning them down really quickly. It's too fast for any of the ramp decks here.

I played this deck in the event (but - 4 Knight of the Ebon Legion + 4 Footlight Fiend).

1 Rix Maadi Reveler (RNA) 109
4 Dreadhorde Butcher (WAR) 194
4 Mayhem Devil (WAR) 204
4 Fanatical Firebrand (RIX) 101
4 Mask of Immolation (M20) 151
4 Priest of Forgotten Gods (RNA) 83
3 Judith, the Scourge Diva (RNA) 185
4 Gutterbones (RNA) 76
3 Chandra, Acolyte of Flame (M20) 126
4 Lightning Strike (XLN) 149
4 Blood Crypt (RNA) 245
4 Dragonskull Summit (XLN) 252
6 Mountain (XLN) 273
5 Swamp (XLN) 269
4 Knight of the Ebon Legion (M20) 105
2 Legion's End (M20) 106