Gregory Ramos was born in Olympus Highlands on Mars in 2529. Later in life, he married, started a family, and decided to join the Office of Naval Intelligence. Even though the missions he would be participating in would be more perilous, working with ONI would mean he would have more time to spend with his family.
- Main article: Halo: Nightfall
Ramos was part of the joint militia/ONI team sent to destroy deposits of a deadly substance found on a fragment of installation 04. After things went downhill, Ramos formed an alliance with Michael Horrigan to ensure that he would escape. Ramos was killed when Horrigan betrayed him by activating an oxygen pack, thus attracting Lekgolo to Ramos and causing them to eat him alive.
In his early teens and twenties, Ramos had a very selfish attitude, believing he only needed to look out for himself. As a result, he had a hard time keeping jobs. On the Alpha shard, his selfish attitude also caused him to betray other members of his team so he could escape.
- Halo: Nightfall (First appearance)