Shakugan No Shana Vol 2

Shakugan no Shana by Yashichiro Takahashi. An Action manga rated Older Teen, published in English by Tokyopop.

High schooler Yuji Sakai discovers that he died some time ago, and that what's left of him is a Torch, a temporary flame that will soon go out. A fierce, red-haired girl called Shana, a warrior who hunts the beings that devour human existence, decides to keep him around.