Shakugan no Shana

In a world overrun by the Crimson Denizens, mysterious beings from a parallel universe that feed on human life energy, the landscape has become a battleground. These ruthless entities leave behind only faint remnants of their victims' souls, known as "Torches," which are destined to be destroyed, erasing all memory of the victims' existence. To combat this invisible menace, warriors known as Flame Hazes wage a relentless fight against the Denizens. Yuuji Sakai's ordinary life as a high school student is disrupted when he is attacked by a Denizen and rescued by a mysterious girl with blazing eyes and crimson hair. However, Yuuji soon discovers that he has been reduced to a Torch, a mere scrap of memory on the verge of being extinguished, leaving him to navigate this treacherous new reality.