Based on the events of the tenth Shakugan no Shana novel.

From Viz:

Yuji has just started a new semester of high school and everything seems to be normal. That all changes when a mysterious man named Friagne begins turning people into blue flames. And wouldn't you know it? Now he's after poor Yuji!
To the rescue comes a girl named Shana. But is she too late? As it turns out, young Yuji may already be dead. What the heck is going on?