Who is the Head of Slytherin House in 'Harry Potter and the Deathly Hallows'?

Answer 1

The position of Headmaster of Hogwarts changed a few times during the movies. Albus Dumbledore served until the fifth movie when he was ousted and replaced with Dolores Umbridge, the High Inquisitor at the time. She was captured by centaurs in the Forbidden Forest and Albus resumed his post. Sadly, Dumbledore was killed in the sixth movie and Minerva McGonagall became acting Headmistress. She was replaced by Severus Snape during Voldemort's domination of the British Wizarding World. After the Battle of Hogwarts, the position was given to Minerva once again and she served until she retired.

Answer 2

Horace Slughorn.