Colonel Alexander Coltrane is the temporary commanding officer of Section 20. He is appointed to the role after Donovan's death, a position he is unhappy with given Section 20's reputation. He initially clashes with Wyatt and McAllister over their methods, but warms to them when they deliver results. Coltrane was once a promising officer in military intelligence until he suffered a breakdown and became an alcoholic. He was subsequently shuffled between desk jobs and kept out of the field and is now regarded as a cautionary tale by other soldiers. He later gives Novin a reprieve after she disobeys a direct order and confronts a friend's killer, reasoning that he can empathise with her loss.