Okay, I've decided on a Grey Seer primer, an all over wash of Hexwraith Flame  and finally a light to medium drybrush of Uluthuan Grey.

How's this sound? Hopefully,  it works out...

Now here's my problem. Im going to make the cloak of my Ghostly Valoris red like the King of the Dead. 

How do I do that, without making it clash with the rest of the model?