Gumdramon is a Mini Dragon Digimon who serves as one of the main characters in the third season of Digimon Fusion. His name and design are derived from Gum Dramon. He is a bipedal creature with a compact build, covered in short purple fur. He has blue eyes and a small pair of yellow wings on his back, which allow him to fly at his running speed. He wears a red vest and has a distinctive white X-shaped scar on his forehead. His most notable physical feature is his flexible, hammer-like tail, called the Shippodzuchi, which can extend to great lengths to be used as a melee weapon. Attached to his tail is a ring known as the Kinkoji, given to him by Sanzomon to prevent him from living a life of self-indulgence, as it inhibits his considerable, unfathomable potential power.

Gumdramon's personality is very mischievous and he is known for being a showoff. Despite his small stature, he frequently proclaims that he is very tough and often refers to himself as the wild child. In order to attract attention, he tends to dive headfirst into dangerous situations and rampages around until he stands out from everyone else. He is incredibly energetic but also reckless, a trait he shares with his human partner, Tagiru Akashi. This shared impulsiveness forms the foundation of their relationship, with both often rushing into a fight without a detailed plan and relying on their quick, powerful barrages of attacks.

The story introduces Gumdramon when Tagiru is pulled into a strange, unstable realm called the DigiQuartz. It is there that they meet and form their partnership. After Tagiru receives a special Xros Loader from the Old Clock Shop Owner, he teams up with Gumdramon to become a Digimon Hunter. Their shared goal is to hunt down rogue Digimon that wander from the Digital World into the DigiQuartz. While Tagiru aims to become the top Digimon Hunter, Gumdramon supports him in these efforts, facing increasingly powerful opponents.

Throughout the series, the bond between Tagiru and Gumdramon is central to the narrative. Their relationship is not without its difficulties, as their stubborn and argumentative natures can lead to conflict. In one instance, after a significant disagreement, Gumdramon temporarily leaves Tagiru to partner with another Hunter. This separation ultimately leads to a reconciliation, strengthening their partnership and mutual understanding. As they face greater challenges together, their teamwork improves, allowing them to overcome powerful adversaries that threaten both the human world and the Digital World.

Gumdramon possesses a body that is very soft and elastic, allowing him to move dynamically and use his whole body like a spring. He uses his extendable tail as his primary weapon in combat. His notable attacks include the Ran-gum Break, where he freely wields his Shippodzuchi as a hammer, and the Jacked Hammer, a technique where he swings down his super-sized tail while performing a forward handspring. Another powerful move is the Fire Vortex, which involves striking a single blow with his tail while performing continuous forward somersaults at high speed to generate flames. He can also use a version of the Ran-gum Break called the Jetscrew Version, which spins his tail like a screw-propeller to move underwater. As the series progresses and he faces greater threats, Gumdramon is able to digivolve into the more powerful Arresterdramon and eventually reach an even more advanced form known as Arresterdramon Superior Mode to combat significant threats like Quartzmon.