I think dat that 1 is the chimaira avatar but im not sure

Basically, its a cheat. Once you get all the avatars that one is still locked. To get it, highlight that avatar, and rotate it anyway you want twic (use l and/or r). On the second rotation, stop when the avatar os facing away from you. Then, press triangle, square, triangle, square, triangle, then x (if not triangle do circle, been a while since I used this). The main screen comes up with WINNER or something like that. And voila, you can now buy.

nope ur all wrong u get it when u finish mission 35 =P

i beat the game with all gold medals did not unlock him