Ulube was originally Neo-Japan's representative in the 12th Gundam fight who made his way to the finals but was defeated by Master Asia. Since then he had become obsessed with Power believing that Power is what rules the Universe and that the Gundam Fight is a facade where it is simply the stronger nations that defeat the weaker nations.
After he learns the existence of Dr. Kasshu's project, the Ultimate Gundam from a jealous Dr. Mikamura, Ulube saw it as the answer to complete his goal, plotting that it was the key to have Neo-Japan become the eternal ruler of the universe, something that he kept secret from Dr. Mikamura who was unaware of Ulube's true desire. Leading a unit of soldiers, they raided Dr. Kasshu's lab, but it went wrong where Dr. Kasshu ordered his son Kyoji Kasshu to flee with the Ultimate Gundam to prevent the military from obtaining it and Mrs. Kasshu was shot protecting her son. While in pursuit Ulube personally witnessed the Ultimate Gundam becoming the Devil Gundam from the impact of the crash, destroying all the mobile suits expect his, which left him with a scar that he was supposedly covered with a metal plate. The reality is that he was infected with DG Cells and only wore the mask to hide this fact.
After Ulube had Kyoji framed as a scapegoat and had Dr. Kasshu placed in cryogenic suspension to silence him, once Dr. Mikamura revealed that the Devil Gundam's self-recovery will complete during the 13th Gundam fight, Ulube decided for Dr. Kasshu's other son Domon compete as their new representative for the 13th Gundam fight. Ulube also chose for Dr. Mikamura's daughter Rain to accompany despite that Dr. Mikamura was uncomfortable to involving her with in this mission. Throughout the series Ulube had faked sympathy for Domon's situation and also pulled favors for him all for the purpose on one day re-obtaining the Devil Gundam.
After the 13th Gundam fight had ended and Kyoji had died to halt the actions of the Devil Gundam with Domon's help who was now aware of the truth, Ulube went into action and had the remains confiscated intending to reuse it for military purposes. Once his men obtaining the research notes from the late Wong Yu Fat, Ulube learned a female the giver of life will make a better host to the Devil Gundam than the body of a man. Ulube decided for Rain to become the new life core unit especially with it becoming easy since Rain had left Domon after she found out the truth about her father's involvement in the Devil Gundam incident. Though Dr. Mikamura had given up on their plan thanks to Rain convincing him, once Ulube mentioned on what he planned to do with Rain, Dr. Mikamura was shocked and tried to help Rain escape only to be shot for his efforts.
Placing Rain into the body of the Devil Gundam, it completely merged with the Neo-Japan colony and placing the colony on wartime alert, after the citizens are secured in the shelters and Ulube kills the remaining military personnel taking full command. He then sends out a message to all the colonies and states the removal of the Gundam Fight and that Neo-Japan will remain as their rulers. Despite the Neo-America colony's attempt to attack, Ulube has the advantage. Domon then arrives, angry that Ulube had manipulated him all along and Ulube decides to finish him off, and though he is close, Domon's Shuffle Alliance teammates arrive and save him. Once the wounded Dr. Mikamura sacrificed his life to give them a fighting chance by releasing Dr. Kasshu's capsule into space and heeding Domon to save Rain and tell her not to blame herself for his actions, the Shuffle Alliance enters the colony and fight through Ulube's traps and release the escape capsules for the citizens in space.
Ulube responds by facing them in the Grand Master Gundam, and reveals that he is now completely covered by the DG Cells, having become a complete servant to the Devil Gundam and losing his mind to where he is now part of the Devil Gundam AI unit's plan to eliminate the Earth. Though Ulube is able to overcome the Shuffle Alliance, through sheer power, he is killed when the five Shuffle Alliance members use their Gundams to combine their power into a single attack. Ulube's last words was the futility in defeating the Devil Gundam, unaware that Domon and Rain would eventually destroy the Devil Gundam together.