Star Wars the tale of Darth Revan.

A storm is coming and there is no escape. Revan hero, traitor, conqueror, villain, savior. A Jedi who left Coruscant to defeat Mandalorians- and returned a disciple of the dark side, bent on destroying the Republic. The Jedi Council gave Revan her life back, but the price of redemption was high. Her memories had been erased. All that's left are nightmares - and deep, abiding fear. What exactly happened beyond the Outer Rim? Revan can't quite remember, yet can't entirely forget. Somehow she stumbled across a terrible secret that threatens the very existence of the Republic. With no idea of what it is, or how to stop it. Revan may very well fail, for she's never faced a more powerful and diabolic enemy. But only death can keep her from trying.