TV-Series
Description
Kyoya Gaen, the young head of Gaen Financial Group, publicly presents a charismatic and polite facade as the benefactor funding Aibo Academy and the producer of Core Deck Cases, including the Dark variants. This amiable image perfectly masks his true, cold-hearted and manipulative nature. He leads the organization Disaster, viewing all interpersonal connections as mere tools for control and discarding allies the moment they cease to be useful.

His striking appearance features white hair with red highlights, including a central strand partially dyed red. He is typically seen in a black turtleneck, a cross necklace, and a long v-neck sweater, with grey slacks and light brown shoes. When activating his Disaster Force ability, his hair elongates, his eyes transform into reptilian slits, and his attire shifts to a more regal style, often including a long coat.

His buddy monster is the Demonic Demise Dragon, Azi Dahaka, from Darkness Dragon World. He wields a powerful unique deck built around the Flag Cards Dragon Ein, Zwei, and Drei, which permit the use of any Dragon attribute card and grant him significant advantages, such as beginning with higher Life points. His strategy centers on the permanent set spell "Dragon Throne," which protects his cards and enables the summoning of immense monsters.

His long-term ambition is to reshape the world from scratch, believing the problems of the adult world are beyond repair. His method involved distributing Dark Cores to children; these devices harness Disaster Force, a power drawn from spatial rifts created by Buddyfight cards. Using this force opened gates to Darkness Dragon World, a key component of his planned takeover, all while he manipulated public perception to cast himself as a savior.

His history with Rouga Aragami is significant, as he provided Rouga with his first Dark Core during their childhood. He maintained a false friendship for years to ensure Rouga's loyalty and employed similar tactics of manipulation and false hope on other Disaster members, including Terumi and Nobari, to secure their service.

During the Gaen Cup tournament he hosted, he publicly revealed Disaster Force and the Dark Cores, swaying public opinion in his favor. This move was calculated to discredit the Buddy Police and justify his technology. He demonstrated a consistent readiness to eliminate failed subordinates, such as ordering Sofia to dispose of Nobari once his corruption of the Buddy Police was complete.

His confrontation with Gao Mikado was the culmination of his initial plan, intending to use Gao's power to fully open the portal to Darkness Dragon World. His defeat resulted from a miscalculation; Gao's Future Force, which he mistook for Disaster Force, instead sealed the portal. Following his loss, all Dark Core replicas were destroyed and evidence linking him to the plot erased, preventing his arrest. He withdrew his influence from Aibo Academy and exhibited a minor change of heart, hesitantly acknowledging Gao's offer of friendship while declining to spend time with him.

He later reappeared, his core motivations unchanged. He provided energy to assist Tasuku Ryuenji's travel to the future and observed the Yamigedo crisis, during which it was revealed he was responsible for providing Ikazuchi with a Dark Core Deck Case through Sofia. He intended to exploit the crisis to present himself as a public hero, showcasing his continued desire for control.

In the Triple D season, he returned with the goal of obtaining the Ultimate Dragon Power to create an unstoppable new Dragon Ein flag and achieve godhood. His Project Triple D involved forcibly assimilating Azi Dahaka through a Fusion Dance to become a deity, which he temporarily accomplished. His new flags, Dragon Zwei and Dragon Drei, granted him even greater combat advantages, including 20 Life points and the ability to transform into a size 10 monster. His declaration of intent to rule as a god on live television finally resulted in his arrest.

His relationship with his buddy, Azi Dahaka, was complex. His refusal to fully share his plans with his buddy meant their combined aspirations never had a full chance of realization, indicating a lack of true partnership.

A later story involved an encounter with Alexander Ankh, crown prince of the Ankh Kingdom. During their meeting, he displayed extensive knowledge of the kingdom's history and its connection to the Dragods, its deities. He questioned the true motives of the Dragods, implying they might have been responsible for releasing the sealed Vanity Husk Destroyer. This confrontation culminated in a Buddyfight against Alexander, illustrating his persistent nature and deep involvement in the world's underlying conflicts.