Want to be universally hated? Try Dimir! Want to get kicked out of your friend group? Try this deck!

Also, Future Sight is the best expansion ever released.

Strategy

This deck focuses on land advantage thanks to our two Grandeur cards. You win by beating down your opponent with Korlash, but you can also try Emrakul, the Aeons Torn because it is cool.

Grandeur

Future Sight introduced a cycle of legendary Grandeur cards which each provide a powerful effect if you discard the same-named legendary card. The blue and black cards are Korlash, Heir to Blackblade and Linessa, Zephyr Mage.

Korlash
Korlash puts two tapped lands into play for each Korlash you discard. Why does Dimir get ramp? Do not ask questions. Pick Ice Tunnel and Contaminated Aquifer first if possible, but Swamp is fine if you have a copy or two of Sunken Hollow in hand.
Korlash is our big chonker; he will probably end games for us when combined with Linessa.

Linessa
Linessa undoes basically everything the opponent did last turn if you can discard two or three copies of her. The fact that she can return a creature, an enchantment, an artifact, and a land per Linessa is disgusting. Thanks to her wizardry, you can tutor for her with Step Through.

Tutoring and Surveilling

Surveiling is a major aspect of the deck thanks to Discovery // Dispersal, Otherwordly Gaze, and Mission Briefing. Generally, you want to put your Grandeur cards in the graveyard because you can bring them back with Echoing Return and Witch's Cottage. This way, you can draw other things.

Step Through can tutor for Linessa specifically whereas Disciple of Deceit can perform a sort of transmute search. Things get tricky with Gifts Ungiven.

Gifts Ungiven
The cards you want to choose with Gifts Ungiven will inevitably change from game to game, but you can game your opponents with these combinations:

• Korlash, Heir to Blackblade; Linessa, Zephyr Mage; Crawl from the Cellar; and Echoing Return. No matter which go to the graveyard, you can bring both Korlash and Linessa back to your hand.
• Korlash, Heir to Blackblade; Linessa, Zephyr Mage; Witch's Cottage; and Mission Briefing. Similar to the last, but it is especially good for value with Echoing Return already in your graveyard.
• Korlash or Linessa; Mission Briefing; Echoing Return; and Crawl from the Cellar. This option maximizes your graveyard return.

Sideboard & Upgrades

The deck is inherently slow and unresponsive. Include some counterspells and creatures for a chance against aggro and control.

Not a budget player or love to proxy? For a better deck, try:

• 4 Watery Grave and 4 Marsh Flats to replace 4 Contaminated Aquifer and 4 Ice Tunnel; you could choose any swamp-fetchland (e.g. Polluted Delta) instead of Marsh Flats, but Marsh Flats is the cheapest fetchland.
• 1 Sea Gate Restoration // Sea Gate, Reborn to replace 1 Swamp
• 4 Infernal Tutor to replace Disciple of Deceit (or step out of Modern for Demonic Tutor)

As for the sideboard,

• Dream Fracture is there for some counterspelling. Its high cost and card-advantage-return make it something of an "ethical counterspell."
• Lots of Surveiling stuff
• Spellweaver Volute is a neat card from Future Sight. It provides lots of value and is a fine alternative to Emrakul.