Amaterasu

This woman is the and is suspected to be the source of power that generates Amaterasu.

Appearance
The First Pillar appears as a naked woman with shoulder-length bright hair, who is regarded as resembling Iris in appearance.

Personality
As shown when she took control of Shinra, this woman showed very manipulative behaviour. She used his resentment towards people branding him as a Devil, his anger at the Demon that destroyed his family and his confused emotions about the Infernal's true identity to direct him.

Her palpable hatred of humanity is felt by Shinra and noted by Haumea. While she controlled Shinra, she tried to convoke him to burn and kill everything and everyone in their path.

Abilities
As the First Pillar, this person possesses the Ignition Ability Adolla Burst. Shinra Kusakabe suspects that she may be the power source to Amaterasu. Like the Black Lady within the Shintai, she is able to appear before other Adolla Burst users through the Adolla Link.

Netherworld arc
When Shinra Kusakabe sleeps before his journey into the Netherworld, the woman appears before him in a dream. He is momentarily awakened by a small earthquake and is confused by the dream, believing that the woman was Iris.

VS. Special Fire Force Company 4 arc
Upon Shinra meeting Sōichirō Arg, the woman connects with Shinra through the Adolla Link, telling him kill Company 4's captain and to let the anger he once directed at the Demon explode before he snaps back to reality. When a controlled Karin interrupts Shinra conversation with Sōichirō to kill him, the woman appears once again. She seemingly taking control of the young officer with the Adolla Link, planning on using his anger to murder the other officers. This leads to them fighting Captain Arg, who successfully manages to force the rabid Shinra outside. While the battle continues, she promises Shinra that they will kill anyone who gets in their way. The battle seems to be in the Adolla pair's favour, until Arthur and Ogun intervene.

While Arthur senses her presence, the knight cannot free Shinra from her control. Arthur, Ogun, Arg and Pan all move to engage the possessed Shinra, ultimately Arthur continues the battle alone. She tells Shinra not to worry about being a hero or a devil, offering to give the boy information about his mother. If he is willing to kill his opponents. During the battle, Arthur is able to counter Shinra's confused arguments for becoming a Devil much to the woman's fury. This fury presses her and Shinra rushing in to finish Arthur, who counters with a barrage of strikes before finally telling Shinra to embrace being a hero once again to protect what he loves. The woman once again pushes Shinra to kill the Knight, claiming that being a killer is much simpler than losing those you love, but Shinra manages to break out from her control. Despite being disappointed by Shinra's unwillingness to kill, she enjoyed their meeting. While refusing to tell Shinra about his mother, the spectre says she will now play with the fifth and latest person to awaken the Adolla Burst.

Fifth Pillar arc
While Inka discusses her love of danger, the woman appears to tell Inka that she'll soon face a danger so great it will make her fall in love. Inka turns to confront the spectre but she disappears. She also appears to tell Shinra that the Fifth Pillar has awakened.

Vs.Holy Sol temple arc
During Shinra's journey back to Tokyo, he sees her in his dream. Believing that she is crying amongst flames hot enough to evaporate her tears, he asks if she is inside Amaterasu. The woman simply gives him a deranged smile and he wakes up.