Like her original counterpart (Lorgar) of the original Warhammer 40k she's a faithful preacher of the empress of humanity and one of the 18 primarchs (in this reality all of them and the emperor are women) and you encounter her before the events of the Horus heresy and the destruction of Monarchia being right now a faithful and upbeat choir girl (or if you pull enough strings..a chaos follower if the user wants) 
Appearance: white bowl cut hair, primarch power armor of gold and grey, she's nice.