Pay a mana. Sacrifice my Sword of the Meek. Make a Thopter, gain a life, trigger my Sword. Rinse, lather, repeat. This simple, clean, powerful engine dominated Extended for months and made my aggro-loving heart sore from grief over the futility of trying to attack for twenty damage.
Somehow, the Thopter-Sword combo has yet to rekindle that magic in Modern since it was unleashed on the format over two months ago. This comes in spite of the concerted efforts of Roanoke's resident Thopter-Sword master, Gerry Thompson, whose U/W Thopter-Sword list failed to do much but help Gerry to his seventh Invitational Top 8.
Well, no offense to Gerry, but maybe he needed to look at the world through Michael Majors's eyes, that is to say through Grixis-colored glasses. Sadly for Michael, it appears Marc (at least I hope their name is Marc) beat him to the punch on a sweet Grixis Thopter-Sword list.
Grixis Control has been a player in Modern for a while now and has plenty of tools to surround the Thopter-Sword engine. Staples like Lightning Bolt, Mana Leak, and Spell Snare are great early game plays to simply negate what your opponent is doing and buy enough time to assemble your combo. Since Thopter-Sword is so powerful, I could see looking to Remand over Mana Leak here, to add some velocity while still accomplishing the goal of maintaining parity in the early turns of the game.
Kolaghan's Command and Cryptic Command are our powerful top-end spells, much as they are in traditional Grixis decks. Kolaghan's Command gets to partner with Snapcaster Mage as it is wont to do, although returning Pia and Kiran Nalaar is quite potent as well. Still, the full four copies sees excessive, as you really do not want to fall behind by drawing too many three-mana spells. Cryptic Command also gives me reservations in a deck that has only fifteen blue sources and little velocity. The existence of five colorless lands makes shifting the manabase to have more blue sources more difficult than usual, so this may be an unfortunate casualty of the manabase.
The reason the colorless lands are so important is because they support the Thopter-Sword engine. Since Sword of the Meek and excess copies of Thopter Foundry are useless in your hand, Thirst for Knowledge steps in to help you filter through these dead cards and find much needed interaction. But Thirst for Knowledge needs more artifacts than these to function properly, which is where Nihil Spellbomb and Darksteel Citadel come in. Academy Ruins gives the deck inevitability going long, so while two may be unnecessary, the first is essential.
These artifacts also give you something to start the engine with when your Sword of the Meek is in the graveyard, an important role that makes their inclusion even more vital. Notably, Pia and Kiran Nalaar is another potential spark plug, and sacrificing Nihil Spellbomb to make a Thopter allows you to still draw a card. Value!
Unsurprisingly, the sideboard has three Crumble to Dust for what is likely a poor Tron matchup, but the rest of it looks like a typical Grixis Control deck. The engine is lean enough to fit in without too much hassle, which is part of its appeal. The one thing I would caution you about is not taxing the weaker mana too much. Try to shift toward two colors with a splash. Personally I like blue and red as base colors, so you can support Serum Visions and Lightning Bolt more easily while sideboarding the discard spells against combo.