Professor/Principal Hans Rotwood (voiced by Paul Rugg) is an antagonist in American Dragon: Jake Long. He used to be a famous professor until his theories on magical creatures humiliated him in front of his peers, destroyed his career as a scientific researcher, got him fired from his job at Hoboken Science Institute and reduced him to a teacher at Millard Fillmore Middle School. As a believer of magical creatures he teaches a class on them but due to his facts being wrong Jake is always confused and has low grades in the class. Rotwood has a notable dislike of Jake largly due to the lack of respect. Rotwood eventully develops a suspicion of Jake and keeps a close eye on him. In Season 2 after the departure of Dolores Derceto Rotwood becomes the principal of Millard Fillmore Middle School and tricks Jake into revealing himself as a dragon to him. In the episode "Magical Enemy Number One" he attempts to make Jake reveal his dragon form by humiliating him at school. By the end of the episode, he gets a personal look at the magical world and is quite delighted though Jake ensures Rotwood has no proof of what he saw. Though waiting to be famous for proving magical creatures exist Rotwood appears to have a true affinity for them. At graduation he and Jake seem to have put their differences aside as they shake hands. In Dreamscape, it is suggested he encoutered a Chimera as a baby.
Professor Rotwood is similar to Denzel Quincy Crocker from The Fairly Odd Parents. Both of their goals is to reveal to the world that magical creatures exist, they both lost their original jobs and were both humilated due to their beliefs in magical creatures, and they are both enemies to the main protagonists (Jake Long and Timmy Turner).