Been wanting to try a five color deck for a while now to make full use of one of the cycles of cards in the last few sets but five color decks have not really been feasible. I had the Sylvan Primordial in a white/green beat down deck last week that no one saw coming and thought it would be really nifty to get ALL the primordials into a single deck.
After tinkering with this in every free minute for the last week this is my answer. I've stripped out a bunch of "would've been nice" type things that seemed a good fit at first (like Fog and quiron dryad)but in the end just slowed the deck down. I also tried it with elves to get the mana and that was just wasted effort. The side board needs some work; especially as Blind Obedience made it into the main deck.
I can generally get a primordial out turn five if I've pulled one and turn four if I'm very lucky. After the first one is out they just spill out as fast as I pull them.
So first things first the primordials all cost seven mana each. They also all claim two mana from their color as part of that seven - so two specific mana and five generic mana each. Damn that's a lot of mana.
In mana ramp/mana fixing we have Avacyn's Pilgrim and Axebane Guardian to produce mana. Gatecreeper Vine will fetch us a basic land and serve to fuel Axebane Guardian. In addition to the creatures we have Druids' Repository (an excellent little enchantment pointed out by a friend at FNM last week) - as this is primarily an aggressive beat down deck fueling the repository with charge counters shouldn't be a problem. Lastly we have Verdant Haven gives me a two for one land producing one of whatever I want it to - the minimal life gain is a nice bonus.
Fog Bank is primarily for one of the best defenses ever, but in this case it also serves to further fuel Axebane Guardian.
Blind Obedience I also somewhat count as defense as it slows my opponent quite a bit and gives me breathing room. The little bit of damage/life gain from the extort is a nice bonus.
Now for the big bad asses of the deck.
Sylvan Primordial lets me destroy any non-creature when it enters the battlefield and fetch a Forest from my deck. Which also means I can fetch a Breeding Pool or a Temple Garden as well.
Luminate Primordial allows me to exile any creature my opponent controls when it enters the battlefield. Sure they gain life for it; but I can handle giving them a little life with this deck if it mean getting a fatty with vigilance on the field AND getting rid of a problem creature. (I'm looking at you Gravecrawler and Lotleth Troll)
Molten Primordial comes in fast with haste and allows me to steal ANY one of my opponents creatures, untap it, give it haste and attack with it when it enters the battlefield. The cherry on this deck would be if I could find a way to add a "sac a creature you control" mechanic without slowing the rest of the deck down; but this will do.
Sepulchral Primordial allows me to permanently (until it dies anyway) steal one of my opponents creatures from their graveyard when it enters the battlefield.
Diluvian Primordial enters the battlefield and steals an instant or sorcery from my opponents graveyard and then exile it.
Gotta love how they all do something as they enter the battlefield; it kind of makes Cloudshift a real nasty card - as well as a defensive measure.
With all the biggies Rancor was a must and needs no explanation or justification.
Land breaks down as four Breeding Pools which serve no worse than a plain Forest if I have no need for the blue mana at the time. two Temple Gardens (will up to four if I can trade for them) and then six Forests and six Plains. The Sylvan Primordial's ability will allow me to grab Breeding Pools or Temple Gardens - so bonus.
