Aleksei Dorne was a male Human who, during the Cold War, initially served the Sith Empire before ultimately defecting to the Galactic Republic.
Aleksei and his sister were born into an esteemed Imperial family on the planet of Dromund Kaas, which was the capital. Consequently, they experienced rapid advancement within the military.
In 3643 BBY, after the Empire disavowed his squad on Nar Shaddaa, Aleksei reached out to his sister. Elara successfully persuaded Aleksei and his unit to abandon the Empire and join the Republic.