Sheppard is the ranking military officer who finds himself being sent to Atlantis because he has the 'Ancient's gene' that manages to turn on the Ancient technology. With much arguing with Weir he allows her to be the 'head of the expedition' until it is clear that it is a military situation, where he will take over. He is not one for authority but respects Weir, in his own way. Sheppard likes to be cautious but is never afraid of a little danger, often taking on the Wraith by his lonesome (even if he wakes up the rest int he process).