An INTP Slytherin will be very intelligent and resourceful. They will be the brain behind operations. They won’t be as assertive or determined as other Slytherins to prove themselves, but they will if they are provoked. They will be more reserved.
An INTJ Slytherin will be much more determined, and although they are introverts, they are more aggressive. They want to prove themselves and their goals, and they make really good leaders. They would rather not lead, but if they feel someone in leadership is not competent, they will step up and take control.