Robert Christianson was the biological father of James Christianson. He held the rank of Admiral in the Systems Alliance, as well as Executive Officer on the SSV Kangchenjunga. He was a survivor of the New York Rapture, and served in the retaking of Staten Island in the aftermath though he obtained no biotic abilities from the exposure. He is killed in 2186 while helping survivors in New York City escape the Reaper Incursion when his ship is split in half by a Reaper laser.