Larsa was awesome. Great Guest and I loved his character development. I'm replaying XII now and Larsa believed in his brother with all his heart. But he sees what Vayne is willing to do throughout the game and finally turns on him.
Loved that.

Also, on the note of him being a few years older...he is quite the cutie pie. ^^
How old is he anyway? I just know he's very nice-looking.