This is up to you or how you want the game to look. If you want your character to stand out or be slightly more visible, add some emission to the material by going to the materials tab in the properties panel and adjusting the “emit” slider. Or you could go with “shadeless”.
If you have a shader or python, you can control which objects the shader does or doesn’t affect by using obj.name.startswith(“blah”) at the end of the script
sce = self.scene
for obj in sce.objects:
if not obj.name.startswith("chara"):
for mesh in obj.meshes:
for material in mesh.materials:
shader = material.getShader()
Which means, "this shader will be applied to the object if the object’s name (i.e. what you named it in the outliner) does not start with “chara”
(Also this is the first time I’m giving advice using a slice of python and I’m a beginner, and not quite qualified to give coding advice, so anyone feel free to chime in and clarify what I just said lol)
EDIT - actually, if you have some visuals or even just a draft, feel free to post some pictures! It would be easier to help give advice on lighting to see the characters in their environment.
If it’s dark, and 3rd person, you can parent a light source above their head to illuminate an area around them.