A large, stocky Latino man with a dusky complexion, Ryu was a test pilot-in-training for the Earth Federation on Side 7. When the colony was attacked by Char Aznable, Ryu took control of the Core Fighter jet to protect the White Base. Being a gentle, caring, considerate comrade, Ryu was the best mediator to ease the tension between the uptight Bright Noa and the young civilian recruits. Ryu often acted as mentor for the young crew members such as Amuro, Hayato and others. Ryu frequently piloted the FF-X7_Core_Fighter, as well as the RX-75-4 Guntank.
When Amuro briefly deserted the White Base and was later imprisoned by Bright upon his return, Ryu still believed in Amuro and tried to convince Bright to let him return to the Gundam. During an invasion by Ramba Ral's forces, Ryu was critically wounded after being shot by Ral. He was held in the White Base infirmary, but managed to escape from White Base unnoticed during an attack by Zeon's forces. Ryu sacrificed his life by crashing a Core Fighter kamikaze-style into Crowley Hamon's Magella Top seconds before she was to destroy the Gundam.
His death moves the entire crew of the White Base to tears and the reality of war truly begins to sink in as everyone feels responsible for his death and even try to call to his spirit for advice later on. In recognition of his bravery, Ryu is posthumously promoted by two ranks.