Unity low frame rate

hi guys,

I'm making a fighting/RPG game but I have a big problem with a frame rate.

I cant put more than 6 chars in the same scene the frame rate goes to 20fps and with 2 or 3 models they are in 60/50fps, the chars are made in Maya and have 2000 vertex each model, each model have 2 toon shaders.

I need to put the shaders self ilumined because with shadows in body the frame rate is really poor.

The frame rate become terrible when I enable the shadows in the floor in camera.

Any suggestion to put more than 20 chars in the same scene rendered at the same time?