All my characters can break the Damage limit if they want but Kimahri (my worst character) rarely does it. I'm just waiting for his attack to rise above 50 though.
Auron sometimes hits for 99,999 damage.
Rikku always hits for 99,999 damage.
Tidus usually hits for 99,999 damage.
Lulu only has an attack of 20 but with magic she can hit for at least 10,000.
Yuna hits for about 30,000.
Wakka hits for 12,000 typically.
Kimahri, like I said, rarely hits for more than 10,000 currently. Once I got his ultimate weapon fully powered I decided to train him.