During Harry Potter's time at Hogwarts, he and his students were never given much help when it came to Defence Against the Dark Arts. With the exception of Remus Lupin, every teacher of the subject left a lot to be desired to say the least. However, when the Dark Lord made his return and the students were in need of teaching the most, they were given their worst teacher yet.
Dumbledore's Army was set up in a rebellious response to Dolores Umbridge's terrible teaching of Defence Against the Dark Arts, and her radical approach to transforming Hogwarts for all the wrong reasons. The students, lacking practical experience in the subject, took it upon themselves to learn defensive spells under the tutelage of 'The Boy Who Lived'.
There are, of course, some key players when it comes to Dumbledore's Army. Hermione was the brains behind it, Harry was the teacher and heart behind the teams efforts, and Ron was there too. Yet as the team went on and the war against Voldemort grew, almost every member of the team had their own part to play.
With very little help coming from any of the Hogwarts staff throughout the fifth Potter movie, Dumbledore's Army had to stand up and be counted, which some did more so than others.
12. Seamus Finnigan
Naturally, in Dumbledore's Army there are some characters who added far more to the cause than others. Seamus Finnigan was shown to do very little for the team other than attend a few sessions, and though he wasn't the only one who acted somewhat as a passenger, he was the only one who joined the team late.
He was also the only one who called Harry out to be a liar in front of the entire Gryffindor common room. While many of the students had their doubts about Harry's story, Seamus openly accused him of fabricating his version of events.
It wasn't until after the Daily Prophet's stories no longer added up that Mr. Finnigan realised Harry was right, and became a member of the Army. It took a lot for him to swallow his pride and apologise to his new Defence Against the Dark Arts teacher, but he should never have put himself in that position in the first place.