Derpy is a derp! Maybe is derpdrop. Hopefully beauty! Is mailingpony of Ponyville. Gray coat, yellow mane. Bubblemark be-hind: POP Pop pop!
Sometimes? Will space outward. But also inward. Eyes like amber pebble rolls or maybe whirlpearl oyster. On busy days? Will wear mail vest, mail cap, mail bags. If off business? Muffin satchel. On lazy days? No clothing at all. Only self.
Derpy's background is not entirely known. She sometimes speaks about Hoofington, where she and her daughter, Dinky, used to live. It's well known that Dinky is a sad, angry child who doesn't get along with her mother, and that Derpy is heartbroken about all she can't do for the daughter she loves. Beyond that, their past is something of a mystery. Derpy drops little snippets here and there, but it's hard to know what to take at face value for a creature so tenuously connected to reality. Talk to her in character if you want to learn more!