Mr. Finsterholz is the owner and operator of Hoargrim's Wands and Alchemical Supplies in the Goblin Market of Chicago. He sold first wands to David Washington, Alexandra Quick, Darla Dearborn, Anna Chu and Angelique Devereaux in the summer of 2007.
In July 2011, he refused to sell a wand to Alexandra Quick after her appeal hearing.
He probably origins from a German-speaking country as he still says "Ja" and "Nein" instead of "Yes" and "No", and his name is German for "dark/sinister wood (as in the material, not the forest)".