Soul Caliber 4; My character keeps randomly Changing?

Question

I have an XBOX 360, and when i play story mode with Nightmare, it randomly switches to Tira, and then randomly back. How do i switch the characters, because i just want to play with Nightmare :P

Answer 1

it happens wen u die but u can manually change but

i cant remember how

so u mite be doing it by accident???????????