Aunt Petunia... Witch in Disgrace!!!
Why does Petunia Dursley know so much about the wizarding world... ?? Because she was once part of it... mrs Evans had two little girls, both of whom developed magical powers... Lily and Petunia both went to Hogwarts, and learned a swell as they could, Lily always being the most able... but Petunia had some extraordinary powers, uncommon even among witches and wizards... Unfortunately, on holiday Petunia met and fell in love with Vernon Dursley, and after trying to gauge his views on magic, found that he was a definite magic hater... so, in order to please the man she loved, she pretended to hate magic too, and hid her powers... she left the Order of the Phoenix just as her special powers were needed most, and as a result, she was stripped of her powers, and exiled to the world of muggles... in order to do penance for her actions, which she realised had endangered the world, she reluctantly agreed to help Albus Dumbledore, her old head of house, to shelter the infant Harry Potter....