Colleen and Crystal Steiger are twin sisters and the heads of Minerva Mining and Mechanics Corporation within the Golden Branch, beholden to a greater Steiger business dynasty spread throughout the OriCon regions of the galaxy. One of them is married, and one isn't, but they both kept their surname.
Crystal is the harsher of the two, and focused on the mining side. Colleen focuses on mechanics and engineering; she was a young mechanical prodigy who invented the Rook.
They are ousted by Orth Godlove in "A Splintered Branch, A Ringing Bell Pt. 1".