The Mysterious Messenger, introduced in Chapter three: Welcome to the Chariot Hotel, is a mysterious allie of Clash Coat that only communicates through messages on her pip buck.
The Mysterious Messenger is a side character in the the Fallout: Equestria side story Fallout: Equestria - Ballad of a Crystal Pony.
(not revealed yet)
First made contact with Clash when she arrived at The Chariot Hotel via her PipBuck. He is also able to enter Clash's subconscious and appear in her dreams commonly as Clash's Dragonaquus Statuette. He also is the one who saved Clash from the irradiated factory floor of the Ironshot Manufacturing Factory and put her on the roof.
Very mysterious, would rather give our a cryptic riddle than straight froward answers.
Has the ability to remotely access Pipbucks.
They have a one way relationship with her because they can send her messages, but Clash has no way of contacting them.