He is never at a point where you won’t have any Stamina left. The best part about him is that he is always gaining Stamina with every turn. Dr. Strange would be the Healer of the group. His Teresing Boost gives himself and your allies a boost in Health and Stamina for a few turns.
He is very good in offensive attacks. When he gets to level 6, he unleashes an attack called Vapors of Valtorr which attacks all enemies and hurts them with Magic damage with every turn.
Dr. Strange is a character that you can build a team around. Since he is constantly gaining Stamina, he never gets tired. And with his other abilities he can make sure your teammates never go tired either.