Echo is an MLP Bat Pony OC.
Being a bat pony, and following the international law of all OC Bat ponies, Echo was trained from a young age to be in the royal guard, despite her large impairment of blindness.
On one night, escorting a group of wagon ponies, the clouds overshadowed moon, halting the caravan's progress. Echo though, could pick out the terrain from the slightest noise deviation, and led the group to safety before the sun rose.
Since then, Echo has been a navigator and escort for all the citizens of Equestria and Diplomats that visit the land.
Her cutie mark is a lit flashlight against a waning crescent moon.