Death Cloud is a black-green control or aggro-control deck dependent on the number of creature it employs. Basically, the deck tries to work itself up to cast the namesake Death Cloud and clean out the table. With Garruk Wildspeaker, Golgari Rot Farm and Life from the Loam it will be much easier to rebuild from the Cloud than for the opponent. In this regard, it is quite similar to the Aggro-Loam decks that existed before Odyssey rotated out of the format and used Devastating Dreams in a similar manner.
There are multiple paths to winning the game depending on the build of the deck. Using Golgari Rot Farm, it is quite easy to revamp the mana production and drop either Ravenous Baloth or Tarmogoyf. Either should be uncontested on an empty board. Treetop Village is used in a similar manner. Other decks rely on Garruk Wildspeaker tokens or may use the same Planeswalker to cast a pseudo-Overrun and stomp down the opponent with Worm Harvest Tokens.