In the English dub of the anime Dragon Ball GT, the character known in the original Japanese version as Mr. Satan is referred to as Hercule. This name change was implemented to avoid religious connotations, with the new name deriving from the heroic figure Hercules from Greek mythology. Hercule is a human martial artist who has held the title of World Martial Arts Champion for many years, a status that has made him incredibly wealthy, famous, and beloved by the general public of Earth. He is the father of Videl, the father-in-law of Son Gohan, and the proud grandfather of Pan.

Hercule possesses an enormous ego and is prone to boasting endlessly about his non-existent strength when compared to the true protectors of the Earth, like Goku. He is often seen as a showboating blowhard and a coward, frequently taking credit for the heroic deeds of others. Despite these glaring flaws, Hercule is fundamentally a decent and kind-hearted person. He genuinely cares about his family and friends, and when truly pushed, he has shown moments of immense bravery and a strong sense of justice. He is not inherently evil; he is simply an extremely arrogant man who is deeply concerned with his public image.

In Dragon Ball GT, Hercule has largely retired from active fighting and lives a comfortable life in his mansion. His most significant role is as the caretaker and best friend of Mr. Buu, the kind-hearted, childlike incarnation of the former monster Majin Buu. Hercule and Mr. Buu share a home and a close bond, often spending their time eating and playing together. When the parasitic alien Baby begins his invasion of Earth, Hercule and Mr. Buu are among those targeted. However, Buu manages to protect Hercule from being possessed. Eventually, Buu is forced to save his friend by absorbing him, keeping him safe inside his own body for a considerable portion of the storyline. This act highlights the deep, genuine friendship that exists between the former champion and the former demon, a relationship that began in the Dragon Ball Z series.

Hercule's relationship with his granddaughter, Pan, is also a key part of his character in GT. He is shown to be extremely protective and doting, often worrying about her safety as she embarks on dangerous adventures into space. While he does not possess the god-like strength of the Saiyans, Hercule is actually a highly skilled martial artist by normal human standards. He has demonstrated feats far beyond any ordinary person, such as punching through a steel bus, tearing multiple phone books in half, and moving faster than the eye can see. However, his abilities, which are entirely based on physical strength and technique without the use of ki energy, are completely insignificant compared to nearly every antagonist and supporting hero in the series. He is, however, incredibly durable and possesses a strange, almost supernatural level of luck, allowing him to take hits from beings like Cell and Omega Shenron and survive with only minor injuries for comedic effect. He never learns to fly or use energy attacks, remaining a representative of the peak of non-ki using human potential.