Hämsterviel seems to have a bit of a Napoleon-complex, as despite his short stature, he has a large, imposing character and wants nothing less than total galactic domination, as he is extremely self-absorbed, viewing no one as his equal. Not to mention, he often acts like a spoiled brat, throwing a tantrum when he doesn't get his way, and will take his frustration out on anyone.
He is cunning, diabolical, and very abusive to his minion, Gantu, whom he frequently assaults with a plethora of poorly-sarcastic, albeit demeaning, insults. He never thanks Gantu, even when he captures the experiments. He also doesn't care about his minions so long as they serve him competently. However, despite Gantu's loyalty, as well as helping him escape jail in Leroy & Stitch, he promptly fired Gantu after Hämsterviel's objectives had been achieved, saying that since he had Leroy, he didn't need Gantu.
Hämsterviel also hates his old business partner, Jumba, as well as Stitch, Lilo, Pleakley, and later Yuna. His schemes have sometimes been directed at them, either to enslave them or even kill them. Originally, he schemed to take the 625 experiments Jumba created before Stitch and use them in his bid to conquer the galaxy, viewing the experiments as his own property because he financed their creation using his shady business deals.
Hämsterviel is a diminutive albino alien scientist who desires to conquer the galaxy. He has a rodent-like appearance with white fur, red eyes, a hamster-like body, a gerbil-like lower body, a rabbit-like face, rabbit-like ears, and wears a red cape with a golden H on the front.
Because Dr. Hämsterviel was imprisoned, he wears a prison jumpsuit covered in horizontal dark and light blue stripes. The former lab partner of Dr. Jumba Jookiba, he now seeks to capture the genetic experiments he helped to create through financing, with the help of the retired Captain Gantu, before Lilo and Stitch. The few times Gantu is able to capture an experiment are coupled with comedic moments, usually at the expense of Hämsterviel.
Much to Hämsterviel's chagrin, a vast majority of the universe mispronounces his name, usually as Hamsterwheel or Hamsterveal, but on some occasions other variations have been used, such as Gerbilviel. He is also often mistaken for a gerbil-like creature, despite his insistence that he is hamster-like (though due to his long ears, buck teeth, and triangular nose he looks more like a rabbit).
Hämsterviel usually works from his "prison cell" which he has set up to be a laboratory, complete with communication and teleportation systems, and can be revealed or hidden using an encrypted voice code. During one furlough from prison, he came to Earth and, disguised as a human, tried to trick aliens into working for him. He managed to fool Stitch and nearly reverted him to his evil destructive programming. Several times, Hämsterviel has been personally affected by some of the experiments. On one occasion, he suffered amnesia and Gantu mocked him by making up embarrassing lies to fill in the blanks. Another time, he was pecked by a love-inducing experiment that caused him to fall in love with Gantu, although he still insulted him like he would on a regular basis.
In Leroy & Stitch, he was broken out of his cell by Gantu. He then used Gantu to force Jumba to create a red version of Stitch named Leroy. Hämsterviel and his new minion Leroy and his clone army then overthrew the Galactic Council. In the end, Hämsterviel and his Leroy army were defeated and taken back to Prison Asteroid K-37, where they were all put in individual prison cells.
- Hämsterviel's design is likely to have been inspired by Dr. Habbitrale, a villain from the video game Disney's Stitch: Experiment 626. Within the Lilo & Stitch universe, it is likely that they are the same species.
- In the first film, a Hämsterviel look-alike can be seen in one of the prison cells on Asteroid K-37.
- Hämsterviel is an expert laser-sword duelist.
- Hämsterviel's phone number is: 555-019-829-3434-533-65-5882.
- His prison in Xenon Sector: Prison Asteroid K-37 is Cell 750.
- Hämsterviel is a play on the term "hamster wheel", an exercise decoration commonly placed inside most hamster enclosures.
- It is unknown if Hämsterviel's accent is supposed to be either French or German, since "Jacques" is obviously French (the equivalent of "John"), and "Hämsterviel" is clearly German-sounding with an accent over the "a" in his last name.
- Accent wise, he sounds like one of the French knights from Monty Python and the Holy Grail, but uses ambiguous language when he speaks.
- People mistake him for a gerbil-like creature or a mouse-like creature, though he insists that he is hamster-like. However, despite this, and the fact that he has the word "hamster" in his name, Hämsterviel actually looks almost exactly like a rabbit, aside from his long, tufted tail.
- He also resembles a rabbit with albinism due to his blood-red eyes and almost complete lack of pigmentation in his fur, though it is unknown if he suffers from the condition himself.
- Hämsterviel appears in the online game Lilo & Stitch: Alien Interception along with Plasmoid, Tank, Dupe, Clyde and Yang.