Elixiah, glad you like it 
I use only Ramon Miranda’s brushes: 99% of the time, the charcoal bundle, and one (modified) brush from his small sketch bundle. For this drawing, I modified the tip of his Blend Rag1 brush with a tip from the Odzuki 3.2 bundle (see image).
I use this for the hairy, scribble-like lines at the base of her neck. Normally, I keep the background and the subject separate, but not in this case.
As for the workflow, I’d like to refer you to this answer I provided:
https://krita-artists.org/t/william/190228/3
For this drawing, I experimented with the Burn Overlay mode. I’ve attached a layered Kra file so you can take a look at it here (wetransfer).