Welcome, bros! Allow me to introduce you to a brew of mine, a combo that will let you sneak into play, without much effort, one of the most powerful cards in the game as soon as turn 4. Interested?
The combo is Darksteel Relic
+
Shape Anew
= Blightsteel Colossus. By playing just those 2 artifacts, Shape Anew will inevitably hit the Colossus. At that point, winning will be easy.
How do we get there? By controlling the game, of course. The goal is to stop the opponent from doing anything, until we can put together the combo.
Now, let's proceed to a card breakdown!
Combo
Darksteel Relic: The artifact we need in play. Since it's indestructible, it's hard to get rid of.
Shape Anew
: Our combo enabler. If it resolves, we can sacrifice the Relic to put into play ...
Blightsteel Colossus: The artifact that leads us to victory. It's important to notice that we MUST NOT draw it, or else Shape Anew will not be able to "find" it. Anyway, we have ways to deal with that, and eventual removal.
Control
Remand: Played as a 4-of, this boy can slow down our opponent while replacing himself. Essential.
Mana Leak: Another 4-of, it's one of the best "almost hard" counters of the game. Early game will take everything, late game can still be useful.
Boomerang
: Still another 4-of, this card is really underestimated. It can bounce anything, even lands. Seriously, lands. Talk about slowing down your opponent.
Dispel: A great card in Modern, it gets a lot of nasty threats, and here it doubles as protection for our mighty Colossus.
Stubborn Denial: Same as Dispel, but it acts as a softer, wider counter until we can get the Colossus on the battlefield. Then it becomes a nightmare.
Vapor Snag
: This card is essential to (temporarily) block any creatures that could give us troubles. Oh, you could even use Unsummon since this deck knows nothing about life totals.
Dig and Tutors
Serum Visions: The best draw spell in Modern, it can scry away things unwanted.
Anticipate: Digging for 3 cards at instant speed is a nice thing to do.
See Beyond: It draws cards less efficiently, but it's necessary to shuffle again the Colossus in your library, if you're unlucky enough to draw it.
Fabricate: It tutors for Darksteel Relic. Could be a Trinket Mage if you like.
Lands
Island: YAY! ISLANDS!
Ghost Quarter: Land hate is necessary in the current meta. We don't want Tron to hurt us now, do we?
Rogue's Passage: The only thing better than having a Blightsteel Colossus on the battlefield is to have an unblockable Blightsteel Colossus on the battlefield.
Academy Ruins: If, by any means, they get rid of our Colossus, or they discard/mill our Relic, this will keep us from scooping.
Tolaria West: See all those lands I mentioned? Here, this tutors for them, and for Relic too. Lovely.
Sideboard
Dispel: Facing one of those pesky Delvers, or something like that? Bring in more of these boys!
Vapor Snag
: Facing one of those pesky Aggro/Beatdown decks? Bring in more of these boys!
Negate: Facing one of those pesky Control/Combo decks (like this one)? Bring in these ... Oh, you got it.
Displacement Wave
: Since we don't play permanents besides lands, this thing bounces off our opponent's board. Destructive against those pesky Tokens.
Hurkyl's Recall: This is here for those pesky (such a nice word, uh?) Affinity decks.
Declaration of Naught: There's always that card that gives you problems in a deck. This easily takes care of it. Oh, and it practically shuts down all-in Combo decks.
Boseiju, Who Shelters All: This land (yes, we're siding a land) makes life much more complicated for Control decks.
Kira, Great Glass-Spinner: If our opponent has ways to hit our Colossus (Auras, Path to Exile, and so on), this can help to protect it.
Inkwell Leviathan
: Blightsteel Colossus's brother. Whenever you feel like to swap the two, do it.
That's it! Hope you like the deck! Feedback is always appreciated!