From Halopedia, the Halo wiki
Marquez was a station technician employed by the Liang-Dortmund Corporation in the effort to de-glass Meridian in the wake of the Human-Covenant War. He was noted as having deceptively boyish features. Both he and Evelyn Collins were acquainted with each other.
During the Guardian attack on October 25, 2558, he was unable to evacuate, becoming trapped on Meridian's surface, and suffered a concussion and two broken legs. Along with Phan, he was taken in and cared for by Doc Cale in Meridian Station. Due to the devastation suffered under the attack, Doc Cale was unable to treat Marquez sufficiently so he remained confined to a cot in the medical building. Despite his condition, Marquez agreed to Collins' plan to try to build a transmitter from spare parts to call for help. Marquez initially struggled, noting he felt "like a kid who just took apart a fridge and is trying to use it to build a slipspace drive," and Doc Cale warned that the exertion and concentration could kill him; however, he ultimately managed to fashion a working transmitter. On October 28, Marquez used this to tap out a call for help for him and the other survivors, but received no response save Cortana's proclamation of the Created and the promise that "All will be dealt with in time."
List of appearances