A member of the Order of the Phoenix, Hogwarts teacher, Tonks’ husband - and a werewolf
I am Remus John Lupin, werewolf, sometimes known as Moony, one of the four creators of the Marauder’s Map
He pushed his greying hair out of his eyes, thought for a moment, then said, ‘That’s where all of this starts...
Harry Potter and the Prisoner of Azkaban
by J.K. Rowling
It has nothing to do with weakness. The Dementors affect you worse than the others because there are horrors in your past that the others don't have.
Remus Lupin Harry Potter and the Prisoner of Azkaban By J.K. Rowling