Severus Snape
Snape is still the tall, dark, cold, and greasy character as before, but his features seem to be softened by the lines in his face, the streaks of white in his hair, and the weight in his eyes.  All masters of Hogwarts are weighed by secrets, but Snape seem to carry them and more.

He is still a feared figure at Hogwarts and his flinty black eyes are the only things that exceed Professor Aquila's in frightening students.