This is the demon god of evil and it was inspired by a serpent creature that I drew way back over 4 years ago, and so I re drew it and added a demon on the end with 2 swords, making him a flaming fire colour adds to the hell design of the usual demons.
I like to do the flame design with felt tips as they blend easier with felt tip pens. to do this I start off with the red and either do the edges of the flame or the centre of the flames, then a light orange colour followed by the yellow pen which seems to blend the colours, sort of like a paint glaze.
Using felt tips could be used as a primary medium, but for me it is for visualizing the colours and moving on from there. I've also been known to sketch with felt pens and often I have gone through packs of felt tips in a day, because they run out of colour.
Top Tip - Save all of your old felt tip pens, because they could come in handy for use with paints and other colour mediums when they dry out, just wet the tips and use them like paint brushes, I always like little recycling tips like this!