My comment is specific to the Geass, really. By all means, nowhere in the anime implies Rollo regrets his actions. If he regrets choosing to contract for the Geass, I imagine he would not use it. But he does.
If by 'regret' you mean his slight inclination to be protective of the locket (thus extended onto his relationship with Lelouch) and enjoying his lifestyle at the Ashford Academy...The way Rollo immediately decided to off Lelouch at the end of episode 3 indicates that he can easily discard his tendencies in favor of his other goals. Certainly it's possible that Rollo may be 'misguided' for now by higher powers, but it seems like he believes in what he's doing.
Rather much like Suzaku in season one, come to think of it.
(no subject)
If by 'regret' you mean his slight inclination to be protective of the locket (thus extended onto his relationship with Lelouch) and enjoying his lifestyle at the Ashford Academy...The way Rollo immediately decided to off Lelouch at the end of episode 3 indicates that he can easily discard his tendencies in favor of his other goals. Certainly it's possible that Rollo may be 'misguided' for now by higher powers, but it seems like he believes in what he's doing.
Rather much like Suzaku in season one, come to think of it.