Cloudpost is one of my favorite lands of all time. It saw play back in Mirrodin Standard as one of two ways to hard cast Tooth and Nail as early as turn four or five, thanks to Sylvan Scrying and Reap and Sow. It was banned in Modern due to the oppressive combination of Cloudpost, Vesuva, and Glimmerpost making to too easy to hard cast Eldrazi early in the game without giving up too much of your early game to aggro. However, all these cards are still legal in Legacy, which means we can do all manner of monstrously big things, especially when you combine the colorless mana from Cloudpost with mana rocks to get bigger faster:

11 Post - Legacy | ROMARIOVIDAL, 5-0 Legacy League

• Creatures (10)
• 1 Emrakul, the Aeons Torn
• 2 Kozilek, the Great Distortion
• 3 Ulamog, the Ceaseless Hunger
• 4 Thought-Knot Seer

• Planeswalkers (4)
• 4 Ugin, the Spirit Dragon

• Sorceries (1)
• 1 All Is Dust

• Artifacts (20)
• 2 Basalt Monolith
• 3 Thran Dynamo
• 3 Trinisphere
• 4 Chalice of the Void
• 4 Grim Monolith
• 4 Voltaic Key

• Lands (25)
• 2 Crystal Vein
• 2 Eldrazi Temple
• 2 Eye of Ugin
• 3 Vesuva
• 4 Ancient Tomb
• 4 City of Traitors
• 4 Cloudpost
• 4 Glimmerpost

• Sideboard (15)
• 3 All Is Dust
• 3 Coercive Portal
• 4 Ensnaring Bridge
• 4 Leyline of the Void
• 1 Trinisphere

Buy This Deck

The key to this deck is that you can use Sol lands like Cloudpost and Ancient Tomb to quickly get Grim Monoliths and Basalt Monoliths on the board. These mana rocks, in conjunction with more Sol lands and Voltaic Key, make it trivial to cast your giant monsters. If you lead on City of Traitors into Grim Monolith, then untap and have Voltaic Key and an Ancient Tomb, you can cast a turn two Ugin. How many decks are going to be able to beat a turn two Ugin?

Of course, the real question isn’t whether you can win if your plan goes undisrupted. The question is whether you can deal with strategies that can interact with your plan. As far as countermagic goes, Trinisphere is one of the best answers to cards like Daze and Force of Will, since your opponents will have to pay three in addition to their alternate costs. Eldrazi titans with cast triggers are another great way to ensure that you get value out of your threats. Kozilek, the Great Distortion is a premier way to fight through counterspells since you get to reload with even more threats to overwhelm your opponent.

If you’re looking for a deck that can just stop your opponent from playing Magic with proactive disruption and then follow up with monstrous threats early in the game, this is a reasonable way to do it. The artifact acceleration is vulnerable to things like Abrupt Decay and counterspells, while the lands are vulnerable to Wasteland, but even with the two of them, you ought to be able to stitch together enough mana to cast some big stuff and crush your opponent with it.