Qualfer Riventzel, more commonly known as "Professor Qualfer" or "Riv" (the latter mainly by Arshes), is a Professor of Swordsmanship at Gaius School for Witchcraft and Wizardry. He teaches the first year Swordsmanship class, but beyond that his subjects are [so far] unknown, although in the first volume of Aventura he was shown to have a considerable mastery over magic. Riventzel also, however, has a half-mask on the left side of his face (viewer's left). The origins or reasons for this mask are as of yet undisclosed. He is also shown to be good friends with Professor Arshes, and in many scenes they are found together. Qualfer is a sort of mentor to Lewin, too.
Riventzel's appearance is quite a contrast to his best friend's (Arshes'). Although there is very little hight difference between them (Arshes being slightly taller), Riv's character is generally made of much darker colors, fitting his more serious and dead-pan personality. His hair is black with a few streaks of white and short, a tiny bit longer than his chin. His eyes are also darker, a deep amethyst purple - a color that some other characters find a little unnerving. Riv's hair is generally straight, but a few strands sometimes stick out in a sort of cowlick. Because Riventzel is a professor, he is not restricted to a specific uniform. He normally wears black and white boots, black pants, a black longsleeved shirt, a black, white, and red cloak, and a belt. On the right side of his face is a half-mask, much like in the Phantom of the Opera. The mask is white, with a crooked (rather deranged looking) smile and some sort of black markings on the forehead. According to Midorikawa, the mask is part of a curse. Lewin, Chris, and Soela once described him as "scary" (partially due to his height).
In the back of volume 3, in the extra comics, Riv is shown wearing some more casaual and modern clothing. In these extras he's depicted wearing black shoes with a buckle and a short heel, black socks, black pants, a sweater, and a black, collared jacket. His hair remains pretty much the same, but he tells Arshes (the hairstylist) to give him a crew cut (which Arshes proceeds to ignore). Riventzel also attempts to get his bangs out of his face using a clip, which easily slips out of his hair. Arshes tries to tie it back with a hairband, but it just sticks straight up.