Disclaimer: I do not own To Aru Majustu no Index.

Note: I was kind of disappointed that the Deep Blood arc didn't have any actual Vampires, so I felt that I should write this. Please review.

Prologue: the Curse

Deep within a great forest, a young girl was on the run. She stayed on the path, not wanting to get lost. Even if she jumped into the forest itself, her pursuers would still find her. She knew that for a fact all too well.

She was dressed in a miko's attire and had long, straight black hair. Her name was Aisa Himegami, also known as Deep Blood to the world of magic.

She looked behind her. Her pursuers were quickly closing in. They looked like humans, but they were different. Right now, their eyes were blood red, and they had long sharp fangs bared. Many of them ran on the path, and some hopped from tree to tree. Others flew on large bat-like wings.

These were Vampires.

The power of Deep Blood was to attract Vampires. No matter how much control the vampires had, they could not resist the sweet scent of her blood.

But that was not the only reason why Aisa was fleeing.

Several Vampires managed to get ahead of her and surrounded her. She had nowhere to run.

As the Vampires approached, they suddenly staggered, as if a mysterious force was draining all of their lifeforce. And as they drew closer, they fell on their knees and crawled, ignoring the mysterious pain inflicted upon them. When they were only a few feet away from the girl, they were down on their bellies. But even as they were dying, they still could not resist the smell of her blood.

Within moments, every single one of the Vampires had died. In the midst of them, Aisa remained untouched.

"Why?" the girl said aloud before she fell on her knees.

This was the curse of the Deep Blood from birth. She was a plague of death to any Vampire.