For an easy start I wanted to learn how to use particle effects in Adobe AfterEffects for admospheric effect. For that, I used this little scetch
And here's the first draft for the animation
At that point, I'm quite happy with how the rain and fog turned out, but there's still room for improvment!
Next step will be to add a nice, gloomy glow effect and movement to branches and details on the mantle.
After that and if everything works in the demo, I'll finish up the drawing to make a fully fledged animated still out of that :)