You know how the leader of a gorilla troop is a Silverback? And also how you could call Darklight/Silverlight to the Shadow Drake?
I thought of a few names:
Silverback
Darkback
Shadowback
Ishmael (book with the same name)
Cysgod (shadow in welsh, I think)
A couple ideas all coming from the chinese monkey king "Sun Wukong"
1.Simply just "Wukong"
2.Since this is a shadow gorilla change "Sun" to Shadow, Moon or something else that relates to shadow
3.Since sun and shadow are sort of opposite elements revert the name to "gnokuw"?
Not sure about the last one but these are a few that comes out on the top of my mind