Victor is a seller known for his experimentation with black powder (aka gun powder). It is very volitiale and his experimentations on it have cost him many a limb. Our first introduction to Victor leaves quite the impression in one's mind. Click the link below and I'm sure you'll agree.
At our introduction to Victor, he is just thrilled to have someone interested in his work. You can easily tell that he hadn't sold to anyone before because not only was his pricing off but his storage for his explosive material is far from standard. The very first encounter with Victor he puts his explosive powder into a hollowed out boars head. Unfortunately as Victor is so happy to have someone interested in his materials, he unknowningly sells this black powder to an enemy of the party. As expected it was a bit disheartenning when his materials where used for malecious intent. It is this revalation that brings Percy ever farther into his protective intitiative trying to prevent this weapon from falling into the wrong hands.
There is one halloween special where the DM (dungeon master) Mathew Mercer dresses up as the shop keep. This is of course later on in the story line where Victor has lost even more limb and sanity to his progression. It is a sight. The drawing is an accurate depiction of some of his character growth but when Mat dresses up as Victor it blows the drawing out of the water. The halloween special also includes the other cast members dressing up as various characters from the campaign. All the cast members dressing up just adds to the hilarity and awe of the entire episode. Click the link bellow for the video I refer to.