David Rockwell Greyson (Service Number: 81219-98219-DG) CC was a Captain in the UNSC Army and was the leader of 196th Engineer Command of the Army Corps of Engineers during the Battle of Earth in 2552. He was later conscripted in the Spartan-IV Program due to his valor during the Sentiment Campaign in November 2555. By 2558, he was the Spartan Commander on board the UNSC Raven's Nest and the leader of Fireteam Guardian.