Gihren Zabi serves as the de facto supreme leader of the Principality of Zeon during the One Year War, holding the positions of military commander-in-chief and highest political authority. As the eldest son of Sovereign Degwin Sodo Zabi, he exhibits exceptional intellect with a reported IQ of 240 and demonstrates significant political skill from his youth, participating in Zeon's independence movement since adolescence. He played key roles during pivotal moments such as Zeon Zum Deikun's declaration of the Republic of Zeon in 0058 at age 14 and Deikun's death in 0068 at age 24. Politically ambitious, Gihren radically reorganized "Zeonism" in 0071 at age 27 and announced the "dominant theory of human survival," positioning Spacenoids as humanity's chosen people. His ultimate goal involved environmental regeneration of Earth through drastic population reduction to 50 million people, necessitating humanity's migration to space. To achieve this vision, he orchestrated the One Year War against the Earth Federation, authorizing extreme measures including nuclear and poison gas attacks on Sides 1, 2, and 4, and the colony drop Operation British despite foreseeing catastrophic environmental damage. Gihren possesses notable oratorical skills, evidenced by his "Sieg Zeon" speech following his brother Garma's death, which effectively rallied Zeon's populace. His leadership style relied on overwhelming firepower and prototype weapons like the MA-08 Big Zam and the Solar Ray superweapon. He maintained a bitter rivalry with his sister Kycilia Zabi, though he underestimated her as a threat. His character draws explicit historical parallels to Adolf Hitler, noted by his father Degwin. Similarities include a "survival of the fittest" ideology positioning Side 3 Spacenoids as superior, masterful public speaking, political usurpation (taking power from Degwin as Hitler did from Hindenburg), adoption of modified Nazi salutes ("Sieg Zeon"), and overreliance on "miracle weapons." Like Hitler, he overestimated his forces' capabilities during decisive battles. In the war's final days, Gihren ordered the Solar Ray's activation against the peace negotiation fleet on December 31, 0079, intentionally killing both his father Degwin and Federation General Revil. This act of patricide was later confirmed by Kycilia, who executed Gihren during the Battle of A Baoa Qu. His death caused critical disruption in Zeon's chain of command, contributing significantly to their defeat. Beyond the One Year War, Gihren's legacy persists through loyalists like the Delaz Fleet, which executed Operation Stardust in UC 0083. His ideology of Spacenoid supremacy also influenced later factions such as the Titans. In the alternate timeline of Mobile Suit Gundam GQuuuuuuX, he survives the war and engages in a cold war with Kycilia. During this period, he develops the Yomagn'tho superweapon, officially for environmental restoration but actually as a deterrent. He is ultimately assassinated by Kycilia via poison gas in UC 0085 during a confrontation about their father's death. The "Plot to Assassinate Gihren" storyline reveals his manipulation of internal dissent. Through his secretary Cecilia Irene, operating under the alias "Reginlief," Gihren orchestrated a fake assassination plot against himself to identify and eliminate political opponents, particularly those loyal to Zeon Deikun's original ideals like Brigadier-General Henri Schlesser. This scheme simultaneously aimed to discredit Kycilia and consolidate his power.