One day, one of the magic mirrors in Twilight’s castle unexpectedly activated. Light flashed and the mirror shattered, but two tiny foals sat where none were before. They were alicorns, and even though they were very young they had cutie marks branded on their flanks. While they seemed to recognize Princess Trixie, when they saw Princess Twilight they immediately exclaimed that she was their mother. Upon further questioning, it was discovered that the two are the “twin” children of Twilight Sparkle and Sunset Shimmer from an alternate universe of strange magic, and they had been sent to this world, earning their cutie marks and their alicornhood in the process, for it was through their combined effort that they were able to reactivate and navigate the portal between worlds.
 
Glister was born a pegasus, and was born to Sunset Shimmer. He’s very laid back and content, and seems to have an intuitive knowledge of what’s happening around him such that he always seems prepared. He adores his “big sister,” Nightfall, amazed by her magic shows and her unique wings, and isn’t often far from her side. When his sister and he were flung into the void between worlds, he was the one who navigated them to the other side, earning his cutie mark.