12/19/18:
This was originally built around seemingly obvious winners: demon of catastrophes, lathliss and banefire. However the removal in this set was too prevalent and the support for those four got very thin after goblin instigator. Lighning mare, the next cheapest creature, isn’t great sac fodder, not enough to make Brawl Bash make sense, and the Sparktongue dragons are just terrible value on their own, even though the lathliss trigger is awesome. Add to that the fact that Banefire is the only removal spell available, red black just isn’t as good as it looks based on its top end. After 3 matches I tried Green Black, hoping the vigilant baloth, blanchwood armor, and some deathtouch could get somewhere. It didn’t.
Blue however may have the card draw to make sure both demons get seen and enough control to survive after they control the first one. The last pick I’m still unsure of. Trying Infernal Scarring first, to boost the damage of the moderate to good hitters like the gearsmiths behind the demons. Or just to make a thopter relevant. Blood Divination may be more what I’m after, or Duress may manage threats I can’t face on the battlefield.
I think I’m excited enough about Totally Lost to mitigate the sadness from not getting to trigger Lathliss.

Earlier note:
Consider for blue splash
Anticipate
Disperse
Totally lost
Dwindle
Divination
Sift

Remove ogres, zombie, duress