Dragonlord Atarka - Aggro Midrange Red/Green Dragons (Modern)

Mana Ramp:
Atarka's Command - This shouldn't be your main mana ramp strategy, but the mode that lets you put a land card from your hand to the battlefield can help you get ahead.
Elvish Mystic - Pretty straightforward.
Sylvan Caryatid - A relatively tough mana producer with hexproof to solidify your ramp.
Courser of Kruphix - Helps you get through your deck faster while providing a nice cushion of Life Points each time you play a land, and is also good to block or whack at your opponent if he or she is open.
Cryptolith Rite - Enables all creatures to tap for any one color of mana.
Eldritch Evolution (Sideboard) - In case your mana ramp isn't fast enough, add this baby.

DRAGONS:
Thunderbreak Regent - Makes players think twice about targeting your dragons.
Stormbreath Dragon - Ready to attack with protection from white and can punish players with large hands if/when it becomes monstrous.
Atarka, World Render - Because double-striking dragons.
Dragonlord Atarka - Because this mama makes an explosive entrance.

Defense:
Atarka's Command - Giving your creatures +1/+1 until end of turn can potentially save your most of your creatures from Languish.
Destructive Revelry (Sideboard) - Enchantment/Artifact hate with BURN!
Display of Dominance (Sideboard) - Fend off those blue/black spells.
Dromoka's Command (Sideboard) - Helps extinguish burn spells; has enchantment hate; buff a creature with +1/+1; starts fights
Kolaghan's Command (Sideboard) - Mainly used to bring back dragons from the graveyard if they get countered or milled. This can also burn and has artifact hate.

Burn:
Atarka's Command - 3 damage to EACH opponent!
Crater's Claws - Used to get rid of unwanted creatures or to finish off your opponent if he or she is left open.
Draconic Roar - More burn to use that can also potentially damage your opponent.
Lightning Bolt - Even MORE BURN!
Arlinn Kord - Gives haste and vigilance, produces wolves, deal 3 damage, buff creatures and give trample. If she gets her Ult off, then it's game over, you win.