Here's the first sketch.
I used pics of a prop replica helmet and traced over it (because I wanted to have the accuracy of a technical drawing).
Then it's vector time:
Rendering shadows to volume and depth.
The background is a massive combination of textures and photoshop effects over one main texture that is a scan I did of candle wax over a plate. Melt the candles and you have a beautiful texture.
And, of course, this is just a fanart and character Kylo Ren belongs to Disney. Please don't sue me.
(typography: Blackletter by Dieter Steffmann)