Awww. Yes. O'aka the 23rd?
O'aka and Rin both give me a warm fuzzy feeling when I buy from them, for different reasons. FFX had the best merchants of any game I've played since
Temple of Apshai.
Whoops, did I just show my age?
Anyway, yes, he's great. Minor spoiler....
Right near the end of the game O'aka gets out of prison. I can't remember exactly when, but he's holed up in the Sphere Theater at Bevelle, and if you talk to him, he explains his little sister was a Summoner who died on a pilgrimage, and he wishes he could've saved her, so he's very glad to help Yuna.
And make a quick buck, but, hey, a man's gotta make a living, right?