Mirtle is a character creation of Thad Donovan (https://www.gaminghonors.com/) which I found in Upwork. I didn't get the job but I decided to paint and visualize his character to sharpen my skills. The art style requirement is 5th Edition D&D style.
Thad's description: Mirtle is a tiefling witch living in toxic volcanic areas along with her huge spider pet. She grew her arachnid arms and brew potions. She is neutral and experiments her potions to anyone - but does not care of the results as she also does not know the effect of her brew.