T'naras is a Sith Inquisitor who rose from being a slave submitted to daily torture and Sith alchemical practices, to one of the most prominent Dark Council members.
He still, to this day, bares the mental, emotional and physical scars that had led to his victory over his master's chains. However, despite all of this, he is known to be reasonably fair, logical, and condemns the practice of torture and subjugation of someone's free will most ardently. Making him stand out among his Sith brethren quite like a sore thumb.
T'naras has a daughter, T'Pana, who has made her legacy through bounty hunting and later becoming adopted into a Mandalorian Clan. He couldn't be prouder of his daughter and wholeheartedly supports her in her adventures across the known galaxy.
This is in reference to SW: TOR's timeline set 3,000 years before the start of Episode 1: The Phantom Menace.