Ramirez was active in the early 2190's.
He was sent with his squad on The Benedict to capture a specimen for the Terran Government. Ramirez was a largely build Marine but was overpowered by fellow Marine Mitch Bueller in a dispute regarding a young woman Bueller was attracted to. Ramirez was taken hostage by pirate forces during an ambush on The Benedict.
Ramirez and the rest of the crew were stranded on the hostile planet without any weapons to defend themselves from the local xenomorph hive. After a lucky break when the local wildlife attacked the pirate Air pods downing several in the process and causing a surviving synthetic to flee to the hive for cover and to Ramirez and his squad. After taking the android hostage and taking his weapons to arm the squad the Marines took the fight to the androids, taking down the stragglers and rearming the squad in the process. After the squad feigned going north through codes spoken over the coms that were hacked, the squad headed south then came back around to throw off the last of the androids. As the squad made their way back to the dropship; Ramirez, on point, went on ahead to the dropship, little did the squad know that the dropship was rigged to blow. When the timer reached zero Ramirez was caught up in the blast when the dropship blew.
Behind the Scenes
In the comic Aliens: Outbreak, Ramirez's role was originally filled by Easley after the Benedict was sent out. Easley taunted Bueller about Billie/ Newt and managed to survive some time on the planet's surface.