For ghostly or otherworldly style flames, which I use to suggest possession or summoning in my Black Legion.

Basecoat

1. Use Ulthuan Grey and cover the areas you wish to be green. You could use Corax White now, as I only used the grey for the coverage over black.
2. Wash White Scar into the recesses of the flames.

Layers

1. Apply Hexwraith Flame over all of the flame. I applied 2 or 3 coats until I was happy with the depth of the green.
2. Once dry, use thinned Incubi Darkness to glaze the tips, pulling the paint to the top of the flame.
3. Add Abaddon Black and glaze the very top.
4. Mix some Hexwraith Flame with White Scar and highlight towards the base of the flames, as the hottest parts are at the base.
5. Use White Scar on the hottest parts.

Finishing Touches

1. Mix Hexwraith Flame with Lahmian Medium , it should be about 1:3 or 1:4 for a very light green mixture. Glaze this over the whole flame to tie together
2. Use the same mixture to add OSL on the nearby surfaces. Add more Hexwraith Flame to deepen the OSL effect where required.
3. Add spots of White Scar on the hottest parts. You can even add some of these as dots around the flame, to represent really hot embers.