I've always beated Tantarian on disc 2. Or then when you have the first chance to do it. I think it's pretty tough. I have to use at least two elixirs every time. I didn't know you can beat Tantarian on disc 3. Shame. I've had Amarant, Zidane, Vivi and Freya everytime with me in that battle - is there even possible to have other characters?