Fen, Forest Goddess

-10: If 4 out of 5 of your Elder Dragons are in the battlefield and one of them is either white or green then target player loses the game.
-5: Go through your library and put a green or white Elder Dragon in your hand. Shuffle your library and scry 3.
X: Tap up to 10 creatures, then increase Fen's loyalty by the devotion to green of those tapped creatures.