Underestimated
Power was her downfall. Power was her saving grace. For as long as she could remember, Hermione was never given much thought. Oh sure she was praised for being the smartest witch to grace Hogwarts' halls in fifty years, but everyone underestimated her. Dumbledore and the Order relied much more than any of them would admit on her brains. Harry and Ron, her supposed friends, used her to pass their classes. These things angered Hermione and why wouldn't they? She was smart of course but she was so much more than that. She was caring, graceful, clever, strong. And there was a part of her that had always protested the side of the Light.
Knowledge was her drug. Knowledge was her motivation. Hermione would do quite a lot to achieve what she wanted. This was especially true when it came to learning and she had learned all she could at Hogwarts. She knew it even if no one else realised it. The professors never taught any of the students anything remotely dark and that really irritated the smart witch. It was in her nature to want to know everything and if she couldn't get what she wanted one place, she would get it somewhere else. That little part of her mind that told her the side of the Light was wrong led her to her downfall.
When she knelt before the Dark Lord, Hermione could tell he was surprised. After she told him what she wanted and what she would give in return, he couldn't resist. After all, Miss. Granger was a very skilled witch, one who would do great things with her full potential unleashed. If this were not enough (and it was not) Lord Voldemort was getting Harry Potter. The Boy Who Lived would be quite dead in a very short time. Hermione was getting what she wanted, unlimited knowledge, and she knew as well as anyone that knowledge is power. Yes, power corrupts and it would certainly corrupt her. That dark piece of her mind would see to that, yet she did not care. Knowledge made her valuable to the Dark Lord and it gave her power. Power that brought her recognition, something she had craved all along. Something that those who called themselves her friends and that those in the Order never gave her.
Before Lord Voldemort case the killing spell at him, Harry looked up at Hermione standing so calmly by the Dark Lord's side. "Why?" "You always did underestimate me," she said will a cold smile reminiscent of her Master's.