This deck’s sole purpose is to force the long game and buy you time until you’re able to pull off the instant win combo. It has decent spot removal, hand disruption, solid draw power and utility to force the long game.
General breakdown strategy as follows:
Demonic Pact and Harmless Offering - (Primary Win Con)
Demonic Pact on its own has some pretty good utility when it comes to keeping you alive long enough to transfer it to your opponent. It’s absolutely devastating to your opponent if you can stack multiple Demonic Pacts. Harmless Offering obviously is what makes your opponent lose. Just be sure you pilot this combo correctly or you can end up killing yourself with it. I have included cards in this deck that will help ensure your killing blow won’t be countered or blow up in your face.
Collective Brutality - (Utility)
A versatile card that can recoup the life loss from Thought Seize and Boseiju. It can also remove threats in the hand or battlefield. Almost as great as K. Command.
Thoughtseize and Thought Erasure (Hand Disruption)
The best defense is a great offense and that's exactly what these cards do. Hand disruption is the bane of control magic users, which helps to cover up this deck's weakness to control magic since we don't want Harmless Offering or our other important spells being countered. I put in 2x Thought Erasure so we can attempt to cantrip faster to find the combo pieces. If going against control magic, use hand disruption defensively; meaning only when you're in position to make an important play. You want to use these cards to bait or rip out counter spells primarily.
Snapcaster Mage - (Utility Graveyard)
What kinda grixis deck would this be if it didn't run snap? Spell recursion is big and there are tons of good spells snap can bring back. More times then not you will be snapping your removal spells; but every now and again you need to snap some hand disruption, removal or cantrip.
Ancestral Vision - (Draw Power)
Ancestral Visions shines if we can suspend it on turn 1. It saves us just in time so we avoid top-decking. The only down-side to this is your opponents have 4 turns to figure out a way to deal with it when it gets cast. Nothing is more annoying then someone hording a counter spell or using Meddling Mage to stop your visions from going off.
Opt - (Draw Power)
While the card does essentially replace itself, it is invaluable to be able to control what you draw next. Control decks simply need to draw cards and the correct ones to be a viable control deck; this card simply fuels that purpose. More importantly however, it can allow you to miracle a Devastation Tide on your opponents turn.
Fatal Push and Lightning Bolt - (Removal)
Fatal Push is a mana efficient spell that will remove most creatures you will find in this format. It’s revolt trigger is easy to pull off with fetch lands. Bolts are all around versatile for removing creatures, walkers or using as a finisher.
Devastation Tide -(Sweeper)
The purpose of this card is two-fold. It severely slows an opponents agro down as well as letting us play Demonic Pact without having the Harmless offering in hand. In fact, the secondary win con is to use damage to win and being able to reset the modes on Pact by bouncing it greatly plays into this strategy. It also lets you re-use your snapcaster. Avoid using if you're about to kill an opponent with the pact combo.
Kolaghan's Command -(Utility)
There are no words to describe how great this card is. It can serve as a mini removal spell and minor hand disruption. More importantly however it can get you back snapcaster and remove pesky artifacts like Aether Vial.
Boseiju, Who Shelters All - (Support)
Is a great way to force the transfer of pact if your opponent is running heavy on counter spells. It's a great card over all that can almost guarantee that your instant or sorcery will resolve.
Creeping Tar Pit
Good to buy time as a chump blocker but mostly great at contributing unhindered damage and removing walkers.
SIDEBOARD:
Sun Droplet - (Support)
Because we have few creatures in this deck it’s fortunate we can buy more time with life gain that has longevity in use and little maintenance. If you can stack multiple sun droplets, your life gain can get out of control pretty fast, buying you tons of time. Low mana cost and no maintenance. If you can stack 2 or 3 sun droplets, a neat trick is to hit yourself with 2 damage with K Command and gain 3 4 or times that life back over 2 upkeep phases. Cripples burn decks. Great against burn decks
Defense Grid
We are a control deck that does not run counter magic. Defense Grid punishes other control decks that use counter magic, giving you a distinct advantage. It makes countering your Harmless Offering much more difficult. This effect gets better if you manage to stack multiple copies.
Damping Sphere
Tron/Storm hate.
Nihil Spellbomb
Graveyard Hate and some draw power.
Witchbane Orb
Great against burn, mill and hand disruption decks.
Dreadbore
Great for walkers like Teferi and JTMS that can put a real hamper on this deck.
Extirpate
Storm and combo hate.
FINAL THOUGHTS:
Even if you can't transfer Demonic Pact; between bolts, tarpits and constantly bouncing pact back to your hand, you should be able to kill with straight damage. Between Thoughtseize, Thought Erasure, K. Command and Colletive Brutality you have tons of hand disruption to help you disarm your opponent in the meantime. That wraps it up folks. I am open to any suggestions as long as they aren't idiotic. Please familiarize yourself with the above guide before leaving feedback. I place a lot of my reasoning for cards into the guide.