Seer doesn't talk much about her past, and what little she does share with Felix is generally vague. Shayle knows next to nothing about the zebra's past.
From what she has said, Seer was a Shaman, presumably in Caesar's Stand, who also branched out to work as a town guard. When asked about why she does both jobs, the mare claims that only being a Shaman isn't enough of a reason to be given a home in the city, and that she needed to do something more useful as well.
The only other known part of her past is that she used to have a daughter, but the filly was taken from her by slavers nearly a decade ago. After the disappearance, she dedicated her life to finding out who took her daughter and where. When she finally found those responsible, she butchered every slaver in the camp in a fit of rage, only later realizing that they were the only lead she had to find her daughter. With nothing else to go on and no further hope of finding her daughter, the mare returned to Caesar's Stand, but still holds an intense hatred for all slavers.
Whatever else her past holds is still unknown, but whatever it is has left her with an extensive skill set and massive amounts of knowledge on the Wasteland, especially the area around New Oatleans.
She exibits knowledge of magical spells and hexes, lockpicking, hacking terminals, and advanced combat capabilities, as well as senses and perception that seems almost impossible for a zebra to have (such as spotting a team of Steel Rangers almost 5 minutes before anyone else could see them). Because of this, she is very confident in her abilities, and very stern in her orders and when she gives advice.