Either way, this whole shadow business reminds me of another character who is said to not be fully dark. What if he focuses on the dark - found within the light, not in absence of it? And what if he's specifically strong in it, because of his light, instead of in spite of it? Ren's use of the word 'Shadow' instead of 'Dark' is interesting. What I understand, him and the knights are more unique in that they use this term instead of calling it the dark. Now this makes sense as they are not sith, but maybe there's more to it?
Dark and Light are viewed as opposites. Dark is when there is no light. However, shadow is specifically something found within the light. There has to actively be light in order for there to be a shadow - and the brighter the light, the darker the shadow.
The Knights of Ren are said to not be Sith, but another sort of dark side user. What if instead of using the dark in the way the sith do - they focus on the dark where the light is blocked? The shadows? I don't know.
Either way, this whole shadow business reminds me of another character who is said to not be fully dark. What if he focuses on the dark - found within the light, not in absence of it? And what if he's specifically strong in it, because of his light, instead of in spite of it?