10Severus Snape - ISTJ
Severus Snape is crafty, resourceful, and holds himself in higher regards than most other people. He is a serious and quiet man, and will not tolerate any foolish wand waving in his classroom. The professor of the subtle sciences of potion making (and double agent for the Order of the
Phoenix) is most definitely an ISTJ.
He is certainly an introvert and prefers to work alone, albeit towards a higher goal. He is a logical thinker and planner, constantly putting himself one step ahead of others so he can continue doing what he needs to. Severus Snape defines the ISTJ's Duty Fulfiller archetype, as his one goal in life was to make sure Lily Evans' child would be kept safe no matter what the cost, giving his own life to do so.