Champion of Rhonas was the inspiration for the deck. As soon as I saw this card, I wanted to cheat in ulamog, the ceasless hunger. I have tried several versions of this deck in a variety of color combinations, and I think that G/W offers the best combo.
Decimator of the Provinces
is a fun 7/7 with trample and haste that can be cheated onto the battlefield with Champion of Rhonas. I only own one copy of Ulamog, the Ceaseless Hunger, so I was looking for an additional target. The trample and haste of this card nicely fits this deck and give opponents fits.
Devoted Crop-Mate has really good targets in
Gust Walker
and Glory-Bound Initiate. This isn't the strongest card in the deck, but its exert ability has been useful more than once.
Glory-Bound Initiate is the other card around which I have been wanting to build a deck. This card is amazing when it is exerted, particularly when it has vigilance. Very good card.
Greenwarden of Murasa is a solid card to cheat in (or cast, if the mana and no Champion of Rhonas is available). Snagging any card out of my graveyard is very nice as an ETB effect, and I get another if it is destroyed.
Gust Walker
is just a solid card that provides a flier when exerted. This has proven to be a very important card when facing the annoying zombies. Fly over them. Its lower CMC means that it can easily be targeted by Fatal Push, but it's worth the try and usually gets a couple of hits in before it is killed.
Manglehorn is here mainly for Aetherworks Marvel decks. It's usually the first card I side out for Tireless Tracker. However, having this main board has been effective against certain decks, so it is fine to keep in the main. It definitely surprises opponents when it shows up game 1.
ulamog, the ceasless hunger is here for one reason only-- to be a target of Champion of Rhonas! Yes, I am well aware that the ETB effects don't trigger from the Champion of Rhonas cheat, but attacking mills 20 cards, so I'm okay with not destroying two target permanents to get Ulamog, the Ceaseless Hunger out on turn 5 and attacking turn 6.
Vizier of the Menagerie has proven to be quite useful. I get to see the next card, and mid-to-late game can even cast those cards. This is particularly critical if I am drawing too much mana. Very good card.