Loghain was at least reluctant, and he didn't act like a father to Cailan for the specific reason of stabbing him in the back later, it just... happened that way because he thought it was the best way to save Ferelden. He had good, but twisted intentions. Still, he had to kill the "only" son of his best friend to do what he did, a man who was like a son to him himself so he gets definite evil points for that.
Sun Li killed the man who was originally supposed to be your caretaker, trained you to kill his brother so he could take the throne, but still trained you with a flaw in your fighting style so he could take you out himself without any real effort. He literally adopted an orphan after killing it's only loving caretaker just to take over the country and killing the grown kid later. Oh and he got mad magic by doing so.
The best thing about it that while he was doing it I was thinking about all the times his lessons seemed a little fishy, and how I should have seen it coming but never did. I just thought he was inflating my ego because Bioware had no real idea how a martial arts academy worked. XD