A control deck that combines the Starfield of Nyx engine with Demonic Pact for card advantage.
The cheap removal spells (notably Dead Weight and Silkwrap) keep aggro decks at bay until I can land a Languish to clear the board.
Duress and Transgress the Mind take out planeswalkers that the deck otherwise struggles with, as well as other problematic cards like counterspells or enchantment removal.
Once I have four mana and have stabilised the board, Demonic Pact nets crazy card advantage; at that point, I should be able to outpace any aggression my opponent still has, or outvalue opposing control decks.
Although the number of cards that can get rid of my own Demonic Pact seems small, in practice Starfield of Nyx is the key - with Demonic Pact providing card advantage, I can build up my enchantment count to turn Demonic Pact into a creature, at which point I can have it deal 4 damage to itself, then recycle it next turn.
Vampiric Rites might seem like an odd choice in a creatureless deck, but the synergy with Starfield of Nyx is worth it. The main downside of Starfield of Nyx is that it makes my enchantments susceptible to creature removal, such that a Languish can completely blow me out. Vampiric Rites provides a sacrifice outlet so I can respond to any removal spell by sacrificing enough enchantments to revert the remaining ones to being noncreatures. It's also the best way to get Demonic Pact off the battlefield.
The planeswalkers provide a steady stream of card advantage, and threaten a win condition if I can't draw Starfield of Nyx. The board wipes make it fairly easy to play a planeswalker onto an empty or almost empty board and take over the game.
Infinite Obliteration in the sideboard is for the ramp matchup, as otherwise World Breaker and Ulamog, the Ceaseless Hunger would destroy the deck. It's also fine against reanimation decks like Zombies.
More discard in the sideboard is great for the slower matchups. Looping Vessel of Malignity forces the opponent to play off the top of their library.
As my mainboard has no creatures, my opponents are likely to sideboard out most of their removal spells. Blood-Cursed Knight is the perfect way to punish that, being a 4/3 lifelink for three mana most of the time. It's also really good against aggro decks that think they can go underneath my enchantments.
I'm not a big fan of Sigil of the Empty Throne, as it requires me to keep casting enchantments, while I can just sit back on Starfield of Nyx and let it win for me. That said, it's still a useful sideboard card against slower decks.
Virulent Plague is great against token decks like Westvale Abbey
decks. Not much else to say about that.
