I have been working on a BW Heartless deck for a few weeks now, and I have found that keeping a full playset of Rune-scarred Demon is key. I end up playing them like Squadron Hawks (using them to fetch the others) and then end the chain with one of the game ending fatties. It also turns the deck into a tool box where I only have to carry one of each of the fatties and pick which one is most useful for each situation.
Modified the deck to play more effectively with or without the heartless summoning. massacre wurm is a beast in this deck. sun Titan may get added for another way to regenerate myr superion plus a sideboard of perilous myrs combos well with them as well.... May replace the angel.
I really hate that Diabolic tutor costs 4......cuz I only play Casual and just use demonic tutor.....anyway I think 2 tutors would help your chances to get the heartless summoning......just that high cost makes it so hard to use effectively
The good thing about the palladium myr and the set of solemn simulacrum is that by turn 4 without a heartless summoning I should be able to at least get out a bloodgift demon or if I'm lucky a Wurmcoil engine
Divinity of Pride is such a good card! One of my first decks I ever owned housed him. I splurged around $80 on cards after playing a booster pack built deck for around 2 months, and the Divine vs. Demonic deck happened to be part of it. I grabbed the best if my white cards and made an angel/lifelink deck with a couple spirit loops, Divinity was a powerhouse!