Spike

Spike Sparkle,born Pendragon, was a dragonlet magically hatched by Twilight Sparkle and became her "#1 assisntant". He is now full grown, with a wife and family, but still stays at the library, helping Twilight and her wife and kids.

Biography
Spike Sparkle was born Pendragon, named by Twilight Sparkle's parents. She, though, insisted on naming him Spike. Afterall, Twilight had hatched him herself, using her advanced magic. This little guy was he ticket to Celestia's School for Gifted Unicorns. He stuck with Twilight all through her years, even after she moved to Ponyville, where he met Sweetie Belle, his future wife. He did have some tough times, using the dragon code and wrecking a party of Pinkie Pie's, but he was loved by (almost) all and did well with his assistant job. Spike an Sweetie Belle first met in carousel botique, when Spike was visiting Rarity, and he actualy developed feeling for her, instead of just "settling for Rarity's sister". They had a weird start with dating, her being a pony and him a dragon, but they smoothed it out and actually got married later on, being blessed with a beautiful kirin filly named Radiance. Spike now works at Tilight Sparkle's library, as an official assistant, and comes home to his wife 4 nights a week, needing to spend the night the other three (friday, saturday and sunday) at Twilight's library.