Toon material shadows problem

Hello everyone, i made a character for a mobile game in Blender Cycles, and i used a toon material as shader. Now, for each toon material i create, i used an ‘Image texture’ as color gradient. I like the result, but i’m trying to work more on the shadows of the character, not cast shadows but of the material itself. What i cannot figure out is if there is any possibility to change the color of this shadows of the material, using Cycles, without changing the lightining. Is possibile to do it ? To change only the color of the shadows ? This is my character

Thank you very much