From Halopedia, the Halo wiki
Dorian had his own problems to deal with as a high school student in 2548 before the Covenant laid siege to Meridian, but once his village went up in flames he found himself stuck above ground and locked out of the town shelter where other survivors had gathered along with three other students: Saskia Nazari, Evelyn Rousseau, and Victor Gallardo. The four youths suddenly were thrust into battle with nothing to aid them but a few scavenged weapons and an injured Spartan super-soldier.
After being exposed to Forerunner artifacts on Meridian, Victor developed a genetic anomaly that prevented his injuries from being healed, something that his friends were also discovered to have. However, Owen-B096 proved to be immune due to the genetic modifications from his Spartan-III augmentations. With the permission of Victor's parents, ONI began the process of augmenting Victor into a Spartan-IV supersoldier in hopes that the genetic modifications he would receive would cure Victor's condition. The attempt appeared to be working and ONI offered Victor's friends the same option. After considering the idea, the rest of the group agreed to become Spartans, knowing that if Victor had been given the choice instead of his parents making it for him, he would've agreed to undergo the procedure.
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