This is a grixis control deck (on the tempo side) with a splash of white. This combination of colors is known as "Yore," which is a reference to the creature, Yore-Tiller Nephilim (hence the four colors of the deck).
This is a control deck, so the main focus is answering everything your opponents play, however this deck also likes to put threats on the board whenever possible. It also plays cards that can be both defensive and aggressive, such as Lingering Souls. The big threats like Inferno Titan and Batterskull often finish out the game, but winning the game by attacking in with small creatures like Creeping Tar Pit and Snapcaster Mage whenever possible is just as viable.
HIDE INSTANTS:
Cryptic Command: This card is one of the best counterspells ever created. The power of cryptic command is reflected in its versatility. It can counter a spell, draw you a card, tap down your opponents' creatures, or bounce a permanent. Because this card is basically foiur cards condensed into one, it allows for the rest of your deck to include a wider range of spells.
Mana Leak: The closest thing we have to Counterspell. This card always works early game and is still pretty good late game as well.
Remand: The most powerful tempo card available in modern. Often times (especially early game), your opponent will tap all of their mana to cast a spell, which means by remanding that spell, you have pretty much played Time Walk. In addition, you draw a card, increasing your card advantage while your opponent's board state is unchanged.
Spell Snare: This counter may seem very conditional, but some of the most popular cards in modern (Tarmogoyf, Dark Confidant, Eidolon of the Great Revel) are two drops.
Lightning Bolt: The best removal removal spell in this deck. The majority of creatures your opponents play early (and even late) game will have 3 or less toughness and the ability to get rid of a creature for just one mana is amazing. Lightning bolt has also helped me win a number of games by burning out the opponent.
Terminate: A great hard removal spell that will eliminate any threat (without hexproof or indestructable of course!) for only two mana.
Electrolyze: This card is all about value. One of the most satisfying things this deck can do is play electrolyze to kill two 1 toughness creatures and draw a card. It's another great tempo card because it acts as limits your opponent's board state in addition to increasing card advantage.
Consume the Meek: The lone board wipe in this deck. Damnation might be better, but consume the meek is good enough that it isn't worth spending $40 on a different board wipe. This spell hits most creatures and the instant speed enables cool tricks (also, Mystical Teachings can fetch it).
Mystical Teachings: Another versatile card which can fetch removal, counterspells, draw spells, and the mighty Snapcaster Mage. Being able to flash back mystical teachings is great as well.
Think Twice: A solid draw spell that can draw you two cards overall. This spell is even better when played with Liliana of the Veil.
SORCERIES:
Cruel Ultimatum: Wow. I bet it took you awhile to read the rules text on that one! While many of the cards in this deck are versatile and can do one of many things, cruel ultimatum literally does EVERYTHING you could possibly need. I won't go over everything this cards does because that would take forever, but I will say that this is either a game winning card, or a card that puts you back in the game from behind. Flashing it back with dnapcaster mage is a humiliating experience for your opponent.
Inquisition of Kozilek: Hand disruption in a control deck is great, and inquisition is better than Thoughtseize mainboard because most of the threats we care about getting rid of will be 3 or less mana.
Lingering Souls: Great finisher, blocker, and discard fodder for Liliana of the Veil. I used to play just three color Grixis but I loved this card co much I added white just so I could play it.
PLANESWALKERS:
Liliana of the Veil: Between cards with flash back like Lingering Souls and Think Twice and recursion like Snapcaster Mage, we make the discard ability not so hard on ourselves while is can be devastating for our opponents. In addition, the sac ability is amazing and can be used to take out annoying creatures like Thrun, the Last Troll and Etched Champion. I've only used the ulimate once, and it is powerful, but expect liliana to die before you get to that point. If you can make your opponent discard a few cards, sac a creature or two, and waste a resource killing liliana, the card has done its job.
CREATURES:
Snapcaster Mage: Maybe the best blue creature ever printed. The mage allow you to reuse a counter or other spell from your graveyard and attack in for a couple turns. Snapcaster mage can also be a great blocker (once in a while if I only have two mana available, I'll flash him in just to block a Goblin Guide or something).
Inferno Titan: One of the most fun creatures to play with. I like this titan because it fits my strategy of controlling the game and being aggressive. The creature effectively plays Lightning Bolt when it enters the battle field and whenever it attacks. This damage can either be used to annihilate opposing creatures or annihilate your opponent directly. Either way inferno titan is going to annihilate something.
Batterskull: Yes, this card is an artifact but it functions as a 4/4 with vigilance and lifelink for 5 mana. Batterskull is needed in this deck because UBR doesn't offer much life gain. Also, it is very difficult to kill batterskull as you can return it to your hand and play it again. Words can not describe the kind of devastation that comes from equipping batterskull to Inferno Titan.
LANDS:
This deck, like most, runs fetches, shocks, checks, and basics. Some of the more interesting lands are described below...
Creeping Tar Pit: A great way to kill your opponent, especially if both players are in top-deck mode. Witch out for removal though. By losing tar pit you've been deprived of both a threat and a land.
Reflecting Pool: The best land you can draw late game and also usually good early game. It is nice when trying to acquire 3 blue mana between 4 lands for casting Cryptic Command.
Urborg, Tomb of Yawgmoth: You won't need another black source after playing this land. It's great for casting a turn three Liliana of the Veil when your first two lands don't produce black.
I also run two white sources, Godless Shrine and Hallowed Fountain, for casting linering souls.