We've seen the four races of destiny. The Cabal, Vex, Hive, and Fallen. But what of the 5th race shown above? Could it be that we will be fighting the first four races tied to the darkness through the early parts of destiny's story, but the 5th race will appear when all of our guardians have gained power, as the darkness' trump card, or even be the darkness itself? This is seen often in anime, when the protagonist gains power and what was once a threat now is now dispatched effortlessly, but then a new challenge appears with power beyond that of the previous enemy's and at most times beyond that of the hero's. Bungie has stated some inspiration of destiny has come from anime, and though it's not likely, this could very well be what they meant, and how they plan to reveal the 5th race and true nature of the Darkness.