We know that she ruled Omega, and is probably an extremely powerful biotic, but in ME3 it was shown that even the Asari councilor was at her beck and call despite having lost her seat of power. Was it ever explained in any of the mini comics how she came to have so much influence or power?
Basically she worked her way up from the bottom, proving that she is capable of being the leader of Omega.
She started as an exotic dancer in the Afterlife club while she plotted how to kill the owner. Once he was dead she claimed ownership and began building alliances and influence on Omega. She eventually overthrew, but did not kill, the former Omega leader, a krogan that goes by the name The Patriarch. She kept him alive and working for her so that others would see him as an example of her power and influence.
Over the years since then she has just built more alliances and influence.