Aside from being the ranking military officer, Sheppard led an exploration team that consisted of Dr. Rodney McKay, Emmagan and Lt. Aiden Ford. After Ford became addicted to the Wraith enzyme and left Atlantis, Ronon Dex joined the team. Sheppard's relaxed command style often put him at odds with his more, by-the-book chief of security, Sergeant Bates, until Bates was severely injured after an attack by a Wraith. During the Wraith attack on Atlantis, Sheppard lost command of the military after the arrival of Colonel Dillon Everett from Stargate Command (SGC).