The Gummi Bears are an anthropomorphic species of bears who have a long and rich history, and are relatively unknown to the humans of the world who believe that they are merely legends and fairy tales. They were the main characters in the animated series Adventures of the Gummi Bears.
According to the show, in ancient times, the Ancient Gummis and humans once lived peacefully together side by side. At some point however, the species was forced into sailing across the sea in search of a new home, due to attacks by evil humans who craved the magical and mechanical advancements of the Gummis. The Ancient Gummis left behind small colonies, such as the main group of the series; the Gummi-Glen Gummis and Barbic Woods Gummis, to care for and watch over the Gummi cities, as well as signal the Ancient Gummis when it was safe to return home.
The Gummi-Glen Gummis are a group of Gummis who live in an hollow tree known as Gummi Glen. At one point, the colony was a major warren, housing hundreds, but at the beginning of the series it has since dwindled to six members, bringing the Gummis of the Glen close to extinction. As their numbers have dwindled, they lost much of their knowledge of their culture and technology, due to not having a Gummi Medallion, which is the only thing that can unlock their Great Book of Gummi, the source of all Gummi wisdom. One day, they come across a young boy named Cavin, who wears a gummi medallion. When the boy accidentally enters Gummi Glen, they are reluctant to trust the boy, but he gains their confidence when he refuses to cause harm to them, and vows to keep them a secret. They then question the boy as to where he got the medallion, which was given to him by his grandfather.
Cavin asks them to help defend his homeland from the villainous Duke Igthorn, but the Gummi's are hesitant, preferring to remain hidden. Cavin leaves, throwing down the medallion as he does so. The Gummi's discover they can use it to open the Great Book of Gummi. From then on, the Gummi Bears then vow to rediscover their heritage, and help Cavin guard his home, the nearby kingdom of Dunwyn.
The Gummi Bears harvest Gummiberries, which grow wild around them in the forest. The bears are able to use the berries to make a powerful juice known as Gummiberry Juice. While the juice merely gives the bears the ability to bounce and escape from danger, it also gives humans temporary super-strength, which eventually makes them a target for the villainous Duke Igthorn. However, they gain allies in the form of Cavin, and later, Princess Calla, the princess of Dunwyn.
Throughout the series, the Gummi bears rediscover many of the secrets created by their ancestors, ranging from dragon decoys to flying machines and even submarines capable of transoceanic journeys and magic that aids them in many of their adventures. They also end up meeting the Barbic Gummis and eventually convince them that not all humans are evil in spite of the mistreatment the Barbics suffered when humans burned down their forest homes. Additionally, they are forced to destroy many of these devices in order to keep Duke Igthorn and his ogre armies from using them to conquer Dunwyn and others like Lady Bane from using their magic to destroy the peace they secretly protect with help from Cavin and Calla. In spite of this, the Gummi-Glen Gummis manage to make contact with the rest of their kin, eventually convincing the Great Gummis to return to their old settlements after they defeat Duke Igthorn for good (though this is never shown onscreen).
- Gruffi Gummi is an old-fashioned bear who prefers to do things "the Gummi way", and the de facto leader of Gummi Glen. An extremely skilled craftsman and mechanic, he is the one that often fixes the old Gummi technology and trap doors, as well as building traps around the Glen to deal with Humans and Ogres. When it comes to building and using tools he is a perfectionist, which can be his undoing at times. However, at other times Gruffi is often the voice of stability when the other Gummis fall into despair.
- Zummi Gummi is an aged bear who is the Gummi-Glen Gummi's "Keeper of Gummi Wisdom" and later the holder of the Gummi-Medallion which he uses to read his magic book to become the group's magician. He is forgetful and clumsy, and his spells tend to backfire. He also had a fear of heights early on.
- Grammi Gummi is another old bear who is the matriarch of Gummi-Glen. She acts as the group's mother, who cooks, cleans, and is the Gummi who prepares the Gummiberry Juice. She holds the secret recipe, and wants to pass it down to Sunni when she is of age. She has a huge rivalry with Gruffi Gummi, and tends to bicker with him over what has to be done.
- Tummi Gummi is an overweight teenager Gummi who enjoys a good meal, and would much rather be eating the gummiberries than picking them. He has a rather relaxed and easygoing personality, which often gets him caught up in Cubbi's schemes. However in dangerous situations Tummi has shown exceptional bravery. Throughout the series he shows signs of being a talented sailor, gardener, artist and craftsman.
- Sunni Gummi is a preteen Gummi, who dreams about becoming a princess just like her best friend the human Princess Calla. Sunni is the most curious about human culture and human fashion, and least concerned with Gummi history. Later in the series she is shown to have a crush on Gusto.
- Cubbi Gummi is the youngest Gummi-Glen Gummi, and dreams of becoming a great Gummi knight. He is incredibly curious and has a tendency to get distracted by the mysterious or the exciting. He sometimes dons a mask and becomes a vigilante known as the "Crimson Avenger". He is best friends with the human Cavin.
- Augustus Gummi is an artistic, individualist Gummi who was stranded on a deserted island for twelve years with his best friend Artie Deco, a wise-talking toucan. Tummi and Gruffi were shipwrecked on Gusto's island, just as a volcano was due to erupt and cause the island to sink into the sea. The three bears worked together and brought Gusto home with them to Gummi Glen at the premiere of Season 3. Gruffi tends to argue with Gusto for his outside-the-box thinking, and how much influence he is on Cubbi and Sunni. He lives by himself in a makeshift apartment behind a waterfall but lives in Gummi Glen when the weather is too harsh.
- The Gummies are very similar to the Ewoks from Star Wars: Return of the Jedi and its cartoon TV show spin-off Ewoks. They are secretive anthropomorphic bear tribes living in forests and facing witches, wizards, and giants. Also, the two tribes live in worlds impregnated by heroic fantasy.
- Gummi Magic cannot be used by humans to harm Gummi bears, as it will instead destroy the human casting the spell.