Monster Strike Elle: Daten no Kakusei

Sixteen-year-old Elle begins hearing a strange sound that nobody else can perceive. It leads her to Amon, a demon who calls himself Lucifer's loyal servant and reveals a truth she can barely accept: Elle is the vessel destined to inherit the fallen king's power.

At the same time, the seal holding back the Seraphim begins to fail, allowing the false god Yaldabaoth to send his forces against the city. The sound in Elle's ears becomes a warning of their arrival, leaving her little time to decide whether she believes in the fate forced upon her. To protect her friends, she must awaken the fallen power within herself and face an enemy determined to erase her before she even understands what she can become.