Major Vernon was a character in Modern Warfare 2: Ghost.
He was part of the second and third team that went after Manuel Roba. During his first encounter, his team was killed except him. He was captured and brainwashed in Coahuila, Mexico. After he was brainwashed, he was released back into the U.S. and asked to make another team to go after Roba. His offer was accepted and they once again went after Roba.
While the team was getting ready, he kept reporting back to Roba. And once the team made their move, he betrayed them to Roba and had the three of them captured and brought back to Roba's brainwashing facility. After the two of the three are brainwashed, Vernon was killed and buried along with Simon Riley.