In the Babylon 5 universe, Lieutenant David Corwin is third in command of B5 behind Captain Sheridan and Susan Ivanova (second in command in Season 5 behind Captain Lochley). A wide-eyed innocent officer who was pretty much caught up in the whole seceeding business. Sheridan and Ivanova debated bringing him in on the conspiracy early on, but decided not to after Ivanova had a private conversation with Corwini about duty and following orders. When B5 did eventually turn against Earth, though, he was fine with it.