This deck has 5 components. I'll cover them here in detail.
A. THE COMBO
Door to Nothingness
+
Overlaid Terrain
Every deck needs a win condition, and this is mine. Overlaid Terrain halves the cost of the door's activation ability, making it plausible. If I manage to draw both cards early on in the game, I can win by turn 7 this way.
B. THE ACCELERANTS
Axebane Guardian| Overgrown Battlement
This deck only has 24 lands--mana acceleration is thus in order. I figured that as a way to improve my deck's consistency I should rely on creature acceleration instead of running 27 lands--such a program might help me get out my fifth land on turn 5, but it's also a waste of cards that could have been spent on something else.
Besides, what if I draw Overlaid Terrain without a
Second Sunrise
to reinforce it? Then I need another source of mana, so as not to waste 4 forests when Terrain comes into play. Axebane Guardian and Overgrown Battlement fill this niche perfectly.
As an additional concern, what if I don't draw Overlaid Terrain? Then I'll need a totally different way of approach to the door's ability. Once again, Axebane Guardian is there for me. Just two on the board with an additional three other creatures is enough to pay for the door right then and there.
C. CARD DRAW
Explore| Harmonize| Wall of Blossoms| Tranquil Thicket| Temple of Plenty
This deck needs a very particular assortment of cards early on in the game in order to function. Card draw will get me to these cards more quickly, whether it be with the unadulterated power of Harmonize, Wall of Blossoms with its extra creature function, or Explore with its mana acceleration. Needless to say, card draw is of the utmost importance for this deck.
D. STALL TACTICS
Hornet Nest|
Mindbender Spores
I need a way to preoccupy my opponent until I can get my combo out--Hornet Nest and Mindbender Spores fulfill this requirement. Either one can shut down the entire board for turns at a time, giving me time to consider my options.
E. PLAN B
Ugin, the Spirit Dragon
Finally, I need a card that will help me through especially bad luck. The Spirit Dragon serves this purpose perfectly. His ultimate will enable me to get the combo on the board guaranteedly, and his other abilities are great for shutting down the board until I can do so.