The Testament of Sister New Devil

After taking Kurumi hostage, Ornis robs Basara of the right arm wielding Bynhildr. Though he lost conciousness from the pain, his sealed power unleashes and goes on a rampage. Their positions are reversed as he corners Ornis with his overwhelming power. However, the moment he tries to silence Ornis for good, a golden chain appears and binds him. When Ornis turns around, he finds Hasegawa Chisato. What secrets has she kept hidden?