World of Warcraft belongs to Blizzard.
This is for people who never got around to finishing the Shadowmoon Valley questline which leads up to this, if you are Horde and have no Alliance characters, for people who don't play, or if you want to watch this again just because.
Here, the Shadowmoon chieftain, Ner'zhul has successfully heralded the rise of of the Dark Star, which is in all reality, a darkened Naaru called K'ara. Velen and Yrel realize the danger that this being could cause, and Velen transfers his holy symbol to Yrel, and then walks towards the dark energy beam and let's loose his power (A.K.A let's loose a radiation of holy energy and then disintegrates into the Light.) Velen's sacrifice shatters the darkness that has K'ara under it's hold and then the newly renewed Naaru emenates a very strong and bright pulse of holy energy, which blinds the Iron Horde Orcs assaulting the Temple of Karabor and empowers the defenders of the Temple. You can pretty much figure out which side wins after this...
