Inori is introduced as the twin sister of the protagonist, Ibuki, a member of the deposed royal family of Nil Kamui. Initially believed to have been killed during the Seven-Year War that saw the nation's fall, she later resurfaces as a candidate to rule the small country, representing the interests of the great nation of Donatia. Her unexpected return is a pivotal moment that forces her brother to confront the dark legacy of their family's connection to the Red Dragon, the former guardian deity of their homeland.

In terms of personality, Inori is portrayed as having a profoundly twisted and unstable mindset, which is often attributed to the corrupting influence of her contract with the Red Dragon. Unlike her brother, who is defined by his reluctance and fear of using his destructive power, Inori is characterized by a disturbing and enthusiastic embrace of her own abilities. Her worldview has been warped to the point where she sees death and resurrection as trivial matters, casually discussing the prospect of killing people and bringing them back to ensure their absolute obedience. This disconnect from the normal value of life gives her a manipulative and sociopathic demeanor, as she believes that creating a kingdom populated by the resurrected is a viable and even ideal path forward. Her logic is described as being twisted, and her madness is a direct consequence of her connection to the Red Dragon, leading her to declare her own intention to become the King of Nil Kamui.

Inori's primary motivation is to become the absolute ruler of Nil Kamui, but her vision for the nation is a dark reflection of her own corrupted nature. She aspires to reign over a kingdom of the resurrected, known as Kaeribito, which she can create and control. She rationalizes that only those who were loyal to the royal family are worthy of being brought back, and she willingly unleashes the Red Dragon to kill the populace, planning to selectively resurrect them as soulless puppets. Her actions set her directly against her brother Ibuki, whom she initially tries to manipulate by turning him against his companions. She sees his friends as enemies and obstacles to be eliminated, and she brings his deceased friend Mashiro back as a Returned One in an attempt to sway him to her side. This deeply personal conflict makes her the story's central antagonist, forcing Ibuki to accept that his own twin has become the primary threat to everything he hopes to protect.

The narrative role Inori plays is that of a dark counterpart to Ibuki. Both are Children of Contract, bound to the Red Dragon, but they manifest this bond in opposite ways. Where Ibuki has the power to destroy, Inori holds the power to resurrect. However, her use of this power comes at a terrible cost, as it perpetuates the Red Dragon's madness and drives her further into insanity. She is revealed to be the true master of the Returned Ones, the puppet-like beings that plague the land, and is directly responsible for the chaos engulfing Nil Kamui. Her actions lead to a fateful confrontation where it becomes clear that to stop the Red Dragon's rampage, Inori herself must be eliminated.

Throughout the story, Inori demonstrates a significant lack of personal development, serving instead as a catalyst for Ibuki's growth. Her descent into madness is already complete upon her introduction, and she remains fixed in her horrifying resolve until the end. Her key relationship is, of course, with her twin brother, Ibuki. The dynamic between them is built on a foundation of shared tragedy and a connection to the Red Dragon, but it is ultimately defined by conflict. She manipulates him while he struggles to reconcile the image of his lost sister with the monster she has become. Her existence forces Ibuki to abandon his naive hopes for a bloodless resolution and accept that saving his country requires him to confront and sacrifice his own flesh and blood.

Inori's most notable ability, derived from her contract with the Red Dragon, is the power to revive the dead. Those she resurrects are known as Kaeribito, or Returned Ones, and they are effectively soulless puppets that follow her will. Unlike a true resurrection, these beings are hollow shells that can transform into violent berserkers when agitated, making them a dangerous and unstable force. Inori wields this ability to build an army of obedient subjects and to psychologically torment her brother by bringing his loved ones back from the dead as empty mockeries of their former selves. She is also deeply connected to the Red Dragon, and her growing madness and wrath allow her to exert a terrible influence over the creature, ultimately taking control of it to serve her own ends. Despite being the true Child of Contract, Ibuki was created as her help, indicating a hierarchy in their shared bond that places her as the primary vessel for the Dragon's will.