Are you using a dynamic light? That might be affecting the brightness.
Here's a picture of a level with two decayed creatures.
As you can see one is near a light and lit up and the other is in the dark, and can only be seen because its a silhouette against the background light.
It would help if you provide some of your settings. I can't remember the exact issue that might cause bright characters. You are using shaders, right?
My ambience is set to 0, lightmapping is set to best for performance.
Another idea is to upgrade to a more recent version of FPSC (latest beta's very good).
"I'm inspired by my own wise quotes, thank you." - Burger, 6/7/12