Nebula: A cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter. 



"We have always been watching, long before they came and murdered the old gods.  By merging with the cosmos itself, forever changing and adapting, we have persevered and we shall continue to observe from a distance, even after all the stars and civilizations in the galaxy extinguish, for that is our role in the tapestry that is life, that is the role of the Nebula Sentinels"