As one of two characters representing the player, Saren's personality is rather malleable. During certain conversations, he has the option of a Joking, Friendly, or Forceful answer. If one trait becomes dominant, then his outlook is flavored by this. A Joking personality sees the humor in a situation (which can irritate more serious characters), Friendly will try to reach goals peacefully, while a Forceful Saren thinks he can dominate any situation.
Saren is extremely loyal to the Amazons, viewing the Citadel as his home despite his harsh upbringing. He doesn't really feel that men are inferior however, and later in the story may even grow bold enough to question Loren on the matter.
Saren, born of an Amazon mother and an enslaved Empire of Man soldier, was raised as a slave as well. His father was captured during The Old War, which the Amazons were not involved in, after making the mistake of trying to ask for their help. Saren's mother was a champion of the Provings. It was rumored that she was stronger than the Queen and that Karen would try to kill her to thwart any plans of usurping her, but actually they were loyal friends. Karen does not know that Saren is her friend's son (since no one ever discusses their son - especially not to the Queen). But Saren knows, so he doesn't fear Karen and instead respects her.