The world has become a slaughtering ground for the Crimson Denizens, mysterious beings from a parallel universe who thrive on the life energy of humans. These merciless murderers only leave behind scant remainders of souls called "Torches," which are mere residues that will eventually be destroyed, along with the very fact of the victims' existence from the minds of the living. In an ambitious endeavor to put an end to this invisible, hungry massacre, warriors called Flame Hazes relentlessly fight these monsters. One fateful day, Yuuji Sakai ceases to be a regular high schooler—he becomes trapped in a crevice of time and is suddenly attacked by a Denizen. Coming to his rescue just in the nick of time is a nameless hunter who seems no different from an ordinary young girl except for her blazing eyes and burning crimson hair. However, before Yuuji can learn anything more about his situation, he discovers that he has already been reduced to a Torch—merely a scrap of memory waiting to be extinguished. [Written by MAL Rewrite]

Oripathy, an incurable disease that slowly crystallizes the bodies of those infected until their deaths. Rhodes Island is a pharmaceutical company that endeavors to find a cure and solve the problems that follow in the disease's wake, and in an attempt to put a stop to the revolt of the terrorist organization known as Reunion Movement whose ultimate goal is the salvation of the Infected, Rhodes Island has formed a contract with the Yanese city of Lungmen and continues its mission there. However, Amiya has found herself despondent since their battle against Skullshatterer, unable to accept the fact they were unable to save Misha. In the meantime, Rhodes Island deploys a reconnaissance squad to an abandoned city discovered in the Lungmen countryside. There, the squad notices a strange phenomenon unfolding before them…

In a world covered by an endless sea of sand, there sails an island known as the Mud Whale. In its interior lies an ancient town, where the majority of its inhabitants are said to be "Marked," a double-edged trait that grants them supernatural abilities at the cost of an untimely death. Chakuro is the village archivist; young and curious, he spends his time documenting the discovery of newfound islands. But each one is like the rest—abandoned save for the remnants of those who lived there long ago. For the first time in six months, another island crosses the horizon, so Chakuro and his friends join the scouting group. During the expedition, they find vestiges of an archaic civilization. And inside one of its crumbling remains, Chakuro discovers a girl who will change his destiny and the world inside the Mud Whale as he knows it. [Written by MAL Rewrite]