Dr. Rupert Jacques von Hämsterviel (better known as "Dr. Hämsterviel") was the main antagonist. of the series; he was seen in Lilo & Stitch as the main villain, and in Lilo & Stitch: The Series as the main antagonist. He wants to break out of prison and take over the Galactic Alliance.
In the 1st film, when Pleakley and the Grand Councilwoman boarded the elevator to Jumba's prison cell, one of the cells appeared to contain Hämsterviel (thus giving him a cameo appearance).
Dr. Hämsterviel is voiced by Jeff Glen Bennett.
Hämsterviel was a partner to Jumba. While Jumba created experiments, Hämsterviel would use his funding with shady businesses. However, over the 25 years of working with him, Hamsterviel always cheated, embarrased and stole from Jumba, and eventually, their partnership ended. Hämsterviel was arrested by the Galactic Federation and Gantu was hired to capture the experiments and transport them to him. Gantu would fail on many occasions, and Hämsterviel would angrily yell at him. On some occasions, he fired him only to rehire him again because all other attempts to find a new henchman ended in failure. In Leroy and Stitch, Gantu broke Hämsterviel out of prison and they went to Jumba's lab to force him to create a red version of Stitch named Leroy. After his latest prison breakout he later landed in Manhattan to infiltrate the Men in Black headquarters and get rid of both the Pelekai family and the MIB since the latter arrested him during the late 90s. He had made clones of Leroy only for them to be blasted and resulting him him being blasted and killed by the MIB and Stitch and his Ohana. In the television series "Stitch and Experiments", Hamsterviel is still in prison and tries to escape in the first episode he ordered Gantu and Reuben to help him escape but then they broke the news to him that they don't work for him anymore. Once hearing that Stitch is taking care of all the experiments he noticed that 627 (now known as Evile) and Leroy were not included and Hamsterviel spent his time in the first season trying to escape. Towards the end of the season he later activated Experiment 628 to be his new henchman much to the chagrin of Evile who had now become a part of the "Ohana". During the course of the series Hamsterviel has even shown some decision making when he was offered by Lady Delia to join her he refused. He even had a recurring dream about what it would be like for him to be rehabilitated, during that time Experiment 000 aka Cyber was unveiled to the galaxy and Hamsterviel even has troubles that he may be too powerful for him to have so in the final episode he saves Stitch and the others by destroying Cyber, 628 and Dark End and has made himself not only a member of the "Ohana" but also a hero.
Films he appeared in:
Lilo and Stitch (cameo)
Stitch! the Movie
Leroy and Stitch
Lilo & Stitch: The Series
Men in Black: The Ohana Syndrome
Stitch and Experiments
I am not gerbil-like! I am hamster-like!
Hamsterviel! It is Hamsterviel!
- Mr. Gantu
- Everyone else (at the end of the series)
Everyone else Dark End Delia 627 Gantu Reuben