McGonagall
Till the end she will be remembered.
This is why!
Through the years many will be forgotten in the wizarding world, some should have been recognised some not as much but for those who tried helped and supported the good and defied the evil none where as prominent as Minerva McGonagall. For unlike harry potter and albus Minerva had a choice.
When other professors fell against the will of evil she stood, when the walls supporting Hogwarts fell she stood. When Dumbledore lay dormant at the base of the astronomy tower she showed no weakness.
Through the reign of voldermort and his death eaters. She never gave in, her one focus was to keep the students at Hogwarts as safe as possible.