Borderlands: The Second Siren
Remember in the main game, the satellite “angel” acts as a plot advancing entity. In The Secret Armory of General Knoxx, you are greeted by Athena, who appears to be a fugitive Siren from her former comrades, the Crimson Lance’s female assassin squads, using the same sort of voiceover plot advancement.
So maybe this will fill in more background about the Soldier (default: Roland) and Siren (default: Lilith) characters? Hmm…