Combined Udesper, known in Japanese as Gattai Udesupā, is a powerful antagonist from the television series Inazuman Flash. This character represents the final and most formidable incarnation of the original Despar Army field commander, Udespar, who was destroyed by the hero Inazuman. Following that defeat, Udespar's remains were salvaged and reconstructed into two separate entities, the bickering brothers Udespar Alpha and Udespar Beta. Alpha embodied physical strength and a straightforward, hotheaded nature, while Beta possessed the majority of the tactical intelligence. Recognizing that their constant infighting made them less effective as a pair, the Despar Army's leader, Führer Geisel, ordered a Despar scientist to perform a merger operation, forcibly fusing the two brothers into a single, unified being known as Combined Udesper.

The personality of Combined Udesper is an amalgamation of its two components, though the fusion process primarily serves to eliminate the weakness of their internal conflict. While Udespar Alpha and Beta constantly argued and competed for the glory of defeating Inazuman, their combined form is single-minded and brutally efficient, focused entirely on destruction. The forced nature of the merger is important to note; Alpha in particular was against the fusion, and even as Combined Udesper, the entity seemed to possess an unstable and aggressive drive to prove its superiority.

Combined Udesper's role in the story is that of the Despar Army's ultimate weapon and a major recurring obstacle for the protagonist, Goro Watari, who transforms into the hero Inazuman. The character is designed to be a more significant threat than any faced before, intended to finally crush the hero who had repeatedly thwarted the army's plans. Its first appearance instills genuine fear and trauma in Goro, showcasing its overwhelming power. The relationship with its creator, Führer Geisel, is that of a master to a tool. Geisel views the combined form as a solution to a problem, ordering its creation, recalling it when a design flaw appears, and ultimately deploying it as his strongest assassin.

The development of Combined Udesper is marked by a significant mechanical flaw. In its initial deployment, the fusion put too much strain on its internal circuits, causing it to overheat after a short period of activity, which forced Geisel to order a retreat and have it separated back into Alpha and Beta. This weakness was later addressed and corrected by the Despar scientists, allowing Combined Udesper to return for a final, decisive battle with no time limit, its eyes and mouth even appearing darker, suggesting an upgraded or more stable state. This final confrontation in a remote mountain village proved to be its last, as Inazuman discovered its hidden vulnerability.

Notably, Combined Udesper possesses impressive defensive and offensive capabilities, but it also has a critical physical weakness. The character boasts incredibly thick armor that can withstand direct hits from missiles capable of destroying buildings, making it nearly impervious to standard attacks. Its physical strength is said to be four times greater than that of the original Udespar, allowing it to easily crush a tank with one hand. Its offensive arsenal includes a right hand shaped like a three-pronged trident claw and a left hand that functions as a long, powerful whip. Its signature technique is the Combined Udesper Drop, where it uses its whip arm to slam the enemy into the ground. Despite its immense power, Combined Udesper has a single, fatal flaw: the area between its eyes is a weak point in its armor. In the final battle, Inazuman exploited this vulnerability by striking it with the Zeber weapon, causing the monster to falter long enough to be finished off by a direct hit from the Zeber Inazuman Flash lightning attack, which destroyed it for good.