Char Aznable is a central figure in Mobile Suit Gundam GQuuuuuuX, portrayed as a renowned ace pilot of the Principality of Zeon forces who holds the rank of lieutenant commander, later rising to captain. He is widely known by the fearsome nickname the Red Comet, a testament to his exceptional speed and combat prowess on the battlefield. His true identity is Casval Daikun, the son of Zeon Zum Deikun, the founder of the Republic of Zeon. This heritage places him at the heart of the conflict, as he harbors a deep-seated hatred for the Zabi family, whom he holds responsible for his father's death. This personal vendetta is a primary driver of his actions, as his decision to join the Zeon military is part of a larger scheme to exact revenge and create a new future for Spacenoids, whom he believes are evolving into advanced beings known as Newtypes.

In terms of personality, Char is depicted as a figure who inspires great loyalty from his subordinates, not only because of his extraordinary piloting skills but also due to his bravery and tactical intelligence in combat. He leads from the front and is known to take on overwhelming odds, though his actions are the result of careful planning rather than recklessness. He is held in high regard by those under his command, who see him as a brilliant and reliable leader. Char also holds a deep appreciation for fellow Newtypes who share his vision for the future of Spacenoids, viewing them as essential allies in his quest to defeat the Zabi family and amass power.

Within the story of GQuuuuuuX, Char's actions deviate significantly from the original Universal Century timeline. In this alternate version of the One Year War, he successfully captures the Earth Federation Forces' prototype mobile suit, the White Gundam, at Side 7. He then repaints this captured machine in his signature red, making it his personal mobile suit, known as the Red Gundam. Later, during a critical battle, Char and his Red Gundam vanish after encountering a mysterious phenomenon called the Zeknova. He eventually returns from this phenomenon and resurfaces under the alias Shirouzu. In this new identity, he works on a project called Solar Ray, secretly altering its inner workings to address the mysteries surrounding the Rose of Sharon and the girl sleeping within it. His relationships with other characters are complex and pivotal. He had a coordinated plan with fellow Newtype Challia Bull to assassinate Kycilia Zabi, a member of the ruling Zabi family. However, after Char succeeds in killing Kycilia, Challia betrays him, revealing his allegiance to Char's sister, Artesia, and condemning Char as someone whose emptiness would lead Zeon to ruin. Char later meets Lalah Sune in a refugee camp on Earth, a significant encounter that echoes his connections from other timelines.

Throughout his journey, Char demonstrates a remarkable ability to plan several steps ahead of his opponents, allowing him to achieve brilliant victories against seemingly insurmountable odds. His talent as a mobile suit pilot is so advanced that he could pilot the captured White Gundam immediately without any need for a manual, despite its systems being different from Zeon's. Researcher Dr. Flanagan recognized Char's abilities as demonstrating the true potential of a Newtype, willingly entrusting him with a Psycommu system for use in battle. Char is also noted for his leadership, capable of inspiring those around him to perform at their best during critical moments. A girl sleeping within the Rose of Sharon remembers Char, hinting at a deeper, mysterious connection between him and the central enigmas of the GQuuuuuuX narrative.