NoHands has been playing a ton of The Demon Seed Warlock, trying out various iterations and offering in-depth explanations about the deck. The following list is from the most recent stream. It's a different take than some of the Stealer of Souls builds we saw (as it doesn't have one). 

Flesh Giants became a consideration, while Soul Rend, Cornelius Roame, and Entitled Customer were put aside. Clearly there are lots of angles to explore here, depending on how the meta shapes up.