You have to load the mod during the character selection screen, and then you will be able to select the marine skin for crystal just like you can the B skin.
Viewing post in Space Marine skin for Crystal NTT comments
i edited previous one, it works yea, but there are ways to make it better! My God Emprah, i already dream of GOLDEN throne, and all!
there was a funny character named Draigo from grey knights
https://www.youtube.com/watch?v=gK38QwAfz3Y he traveled warp just like our heroes do!