Astoria Malfoy née Greengrass: Wife of One, Mother of One

Astoria Greengrass at fifteen was not the impressionable weak minded fourth year one might expect. She didn't agree with her parents' ideals, but she didn't exactly disagree with them either (And isn't her life just full of contradictions). She knew that she was better than any muggle, but she also knew she was better than any pureblood as well. Blood didn't really matter, at least not to Astoria. So this war seems utterly foolish t her.

When a prefect (a non Slytherin one so he looks at her with something akin to disgust) interrupts her Transfiguration class with summons for her from Dumbledore she actually is reluctant, she was enjoying this lesson and she knows that the headmaster must want something from her.

Dumbledore offers her a lemon drop before dropping the pretenses. He tells her that he chose her over her sister because apparently she is both smarter and an "exemplary Slytherin" unlike her sister (she knows this means that her sister is actually nice, while Astoria is a manipulative bitch). He also adds that her youth and gender will make her less of a suspect. He wants her to become his insider on the Slytherin house, and more importantly, his insider on Draco Malfoy. Of course she will get benefits, rights to the prefects bathroom for example, and an 'allowance' of twenty galleons a week. But more importantly, he will give her family the same protection that he gave Snape after the first war. So she carries out his orders and gets close to Draco and warns him on each attempt Draco makes on his life. It's startlingly easy to get Draco to trust her, but even easier to trust him herself. And she doesn't want him to succeed (his soul is much too pure), but she doesn't want him to fail either (she is very aware of just what the Dark Lord's wrath intails).

Because she's gone against everything being a Slytherin has taught her and fallen in love with him. So she doesn't tell Dumbledore of Draco's plans with the vanishing cabinet and she plans to step in before Draco can kill the old man and kill him herself. Except her older sister locks her in her room to keep her safe. But it doesn't matter that she let an old man get killed, because no one will ever know that she could have warned him. Her secret died with him, and no one (especially not her husband) will ever find out why she took a sudden interest in Draco Malfoy's well being in her fourth year at Hogwarts.