SORCERIES
Beseech the Queen- Tutors in the deck are mostly used to grab Doomsday, which you only need 3 lands to grab w/ this card, and being able to pay 6 life to cast this card for free is incredibly powerful.
Bubbling Muck- The version of High Tide, allows us to gain a ton of mana, which allows for early combos.
Cruel Bargain & Infernal Contract- used to draw the last 4 cards of your deck when you use Doomsday.
Dark Petition- Tutors up a card and gives you 3 mana, if you pay 4 life to cast this card using K'rrik, you basically recycle the 3 mana that you used to cast this spell.
Dead of Winter- a low drop board wipe at 3 mana, making it incredibly efficient.
Demonic Tutor, Diabolic Tutor, & Grim Tutor- are generic solid tutors, Grim and Diabolic become powerful in this deck since their mana in their mana cost can be paid w/ life.
Dimir Machinations- used to transmute into Doomsday since it is a 3 cmc card
Doomsday- the key combo card in the deck (see combo section for details.
Drill Bit, Duress, Inquisition of Kozilek, Thoughtseize, & Unmask- used to protect yourself when going off w/ the Doomsday combo, and since they cost 1 , you can just pay 2 life to cast them.
Exsanguinate- this is a mono- deck, so you can generate a lot of mana using Cabal Coffers, Bubbling Muck, & Rain of Filth, and this is a great mana sink, especially since this deck is incredibly hungry for life.
Imperial Seal- a solid tutor.
Massacre- is often a free -2/-2 effect that can hit a lot of opponents creatures, especially in c-EDH, where most creatures are low drops, like stax creatures and mana dorks, luckily K'rrik can dodge the -2/-2, since he gets a +1/+1 counter whenever you cast a card.
Nighthaze- is a cantrip effect that you use to draw after you use Doomsday.
Night's Whisper, & Sign in Blood- generic card draw effects.
Razaketh's Rite- is a tutor and a cycle effect.
Scheming Symmetry- the deck runs a lot of cantrips and cards w/ cycling, so you should be able to draw the card that you searched for right after using this card.
Tendrils of Agony- a storm effect that has a the much desired benefit of gaining you life.
Toxic Deluge- is a solid and efficient board wipe.
ARTIFACTS
Aetherflux Reservoir- used to win when storming off after you've used Ad Nauseam and gaining life is obviously incredibly useful.
Bolas's Citadel- this card's 3 mana symbols, means you can cast this card for 6 life and 3 mana, and it's ability works great in a c-EDH deck, where decks run little land.
Chrome Mox, Mana Crypt, Mana Vault, Mox Diamond, & Sol Ring- are the auto-include mana rocks that go into any c-EDH deck
Expedition Map- is used to grab Cabal Coffers, or Urborg, Tomb of Yawgmoth or Deserted Temple if you already have Cabal Coffers
Fellwar Stone, Mind Stone, Arcane Signet, & Thought Vessel- 2 cmc mana rocks that help ramp into K'rrik.
Jet Medallion- the colorless part of the cost of cards is often the only thing we need to pay for, so this card really helps to cast cards in the deck.
Lotus Petal- is a great card for any deck that wants to combo off as quickly as possible, getting you a one time use free mana.
Sensei's Divining Top- K'rrik doesn't have card advantage attached to him, so Sensei's efficient top of deck manipulation helps make the deck more efficient.
CREATURES
Blood Celebrant- when combined w/ K'rrik you can pay 3 life to get 1 mana, basically allowing you to play cards through paying life.
Blood Pet- is used to net 1 mana, since you can play this card for 2 life.
Carrion Feeder- a key part of the finisher of the Doomsday combo (see combo section).
Crypt Ghast- doubles the mana that your swamps produce, which is obviously good, plus extort is basically free since you pay 2 life to gain 3 life (if there are 3 opponents).
Dark Confidant- is a solid card draw effect for only 2 mana.
Mikaeus, the Unhallowed- is a key part of the win condition when you use Doomsday (see combo section).
Skirge Familiar- is used to get mana when drawing a ton of cards using something like Ad Nauseam
Vilis, Broker of Blood- you are obviously going to be paying a lot of life, so Vilis is going to draw you a ton of cards.
Walking Ballista- a another key part of the finisher of the Doomsday combo (see combo section).
ENCHANTMENTS
Font of Agonies- this deck pays life constantly, so you should have a ton of counters on this enchantment, meaning you can continually machine gun down your opponents' creatures, you can even use the ability for 1 colorless mana and 2 life.
Greed- allows you to pay 4 life to draw a card.
Infernal Darkness- turns all lands into mana only producing lands, which of course doesn't effect us, but can completely cripple our opponents, and the cumulative upkeep cost can be pay w/ life using K'rrik.
Necropotence- is an incredibly powerful card that is an auto-include in any mono- deck.
Pestilence- ability can be payed using 2 life and is great at killing low toughness creatures like mana dorks.
INSTANTS
Ad Nauseam- is used to draw enough cards to storm off.
Aphotic Wisps, Cremate, Fade from Memory, &; Scarab Feast- are cantrip/cycle cards that are used to draw Cruel Bargin/Infernal Contract when you use Doomsday.
Cabal Ritual, & Dark Ritual- are ritual effects that can ramp you up quickly.
Cling to Dust- is a solid cycling effect and can be used as a continual draw effect, by paying for its escape cost.
Imp's Mischief- gives you a way to interact w/ instants an sorceries w/ targets.
Rain of Filth- gives you a way to get extra mana in a pinch.
Sacrifice- used as part of the combo finisher (see combo section).
Snuff Out- has an alternative casting cost, which allows you to cast this card for free.
Sudden Spoiling- turns one opponent's creatures into 0/2 w/ no ability, which is used to stop creature based combos.
Vampiric Tutor- another obviously good tutor.
LANDS
Ancient Tomb- is already a solid and powerful land, but it works especially great in this deck, since colorless mana is often the only mana you need to pay for since K'rrik turns into .
Barren Moor- another cycle effect, this one attached to a land.
Cabal Coffers- is great in a mono- deck, that can net you a ton of mana.
Deserted Temple- is used to untap Cabal Coffers.
x24 Snow-Covered Swamp- we run snow lands for Dead of Winter, we want to run as many swamps as possible for Cabal Coffers, and running a lot of basics helps against Blood Moon and Back to Basics.
Urborg, Tomb of Yawgmoth- used to help w/ Cabal Coffers.