Javier Ramirez was a soldier mentioned in Call of Duty: Black Ops III and seen in the comic.
Ramirez was part of Black Ops team Phi and worked under Dylan Stone, along with Alice Conrad and Joseph Fierro. On June 2nd, 2064, Ramierz and his comrades were sent to investigate the abandoned Coalescence Corporation headquarters in the Singapore Quarantine Zone, due to the activity of the local criminal syndicate, the 54 Immortals, triggering a distress signal inside the facility. There Ramierez and his comrades discovered a CIA black project known as SP/CORVUS, which was an illegal human test program that had inadvertently caused the Singapore disaster which killed 300,000 people.
The CIA could not let this knowledge become public and planned to kill Ramierz and the rest of his team, planning to call the team back to a black station and then assassinating them. However, Stone's team caught wind of the plan and slaughtered the black station staff first. Stone and his team then planned to defect to the Common Defense Pact while also hunting down those responsible for the program. Stone's team fled Singapore to Egypt but it would appear that Ramierz remained behind at the abandoned Coalescence headquarters, uploading classified intelligence from the building's servers. It was here he was unexpectedly encountered by John Taylor and his team. He was captured and interrogated, ultimately revealing what Stone's team was doing and where they were headed. After this, he was killed by Jacob Hendricks, which distressed Hendricks as the two had been friends.
In the simulation created by Corvus for the Player, Ramierez was replaced by Sebastian Diaz. While in the simulation Diaz connects himself to the servers using his Direct Neural Interface (DNI), Ramierez did not do this in real life as he did not possess a DNI and would have instead accessed the servers using conventional means.