The deck is aptly named. You'll stir up a nest when you place the Faeria Tree or Doomgate and your opponent will try to rush you to take them out. If not, you'll get to create your own swarm using the Carassius, and either Aurora's Creation or Gemshell Tortoise or both.
There are lots of ways to build up the Gate in this deck sacrificing creatures, but the most useful has to be using the Architect's gift ability on it (also useful for quickly finishing the Faeria Tree). It's actually kind sick on how fast it levels the Gate up.
It may take a little time to get the lands in play that you need, hence the Wood and Water Elementals. (FYI, although it is a multi-color deck, its concentration is in Blue).
There are a lot of ways to draw cards in this deck to make sure you get what you need (actually a detriment if overused, I burned cards in a couple of games).
Magda and Fugoro are just finishing touches to help out the deck. Specifically, if you want to use Fugoro to make all your creatures a Ostregoth.