Seeing as how Delores Umbridge wouldn't teach them anything about the Dark Arts,I'd definitely have to say Remus Lupin

At least Lupin is Affable, Friendly, Kind-Hearted and Compassionate to his Students, and He gave a nice bar of Chocolate to Harry Potter.

Given that he does actually teach the subject, while she reads from a theory-only textbook.

Umbridge is just the worst anything lmao.

Umbridge didn't even teach them anything. All she did was abuse her power.

Writing blood quills is horrible, sadistic and cruel, but giving out a bar of chocolate is better.

You are all forgetting one important thing. She willingly JOINED VOLDEMORT'S SIDE!

At least Remus Lupin and Mad-Eye Moody are the Members of The Order Of The Phoenix.

@PYRUS4EVR - did the majority of the wizarding population actually know that Voldemort had taken over during the seventh book? I thought that Voldemort and the Death Eaters were working through an Imperiused new Minister for Magic, and while people would have obviously noticed a huge change in policy and government style they were basically all in denial. Umbridge was going along with the current attitude which was keeping her in power, but she wasn't knowingly/willingly supporting Voldemort.

Ok.