Intro
Rien (Hangul: 뤼엔, Iw-ien) is an Oracle's Proxy of the Index and the master of Sora, as well as being one of the five parental figures assigned to training Yoshihide as a Nursefather of the House of Spiders. He is a major antagonist introduced in Canto IX: The Unsevering.
Appearance
Rien is a tall man with pale skin, black hair with silver strands, and a right eye featuring a golden pupil. The left side of his face is concealed behind a porcelain mask, the base of the mask being white, with a golden trim, used to obscure visible burns. The mask features a large crack along it. He wears a black suit jacket with golden buttons and an Index symbol on its left shoulder, with two similarly gold chevrons beneath it. His dress pants and shoes carry the same color as the rest of his suit, with the soles of his shoes having golden trim. Beneath his suit jacket, he wears a plain white dress shirt and black tie. He wears white gloves on his hands. In combat, he wields a golden vial with a chain on it, which allows for a ferrofluid-like liquid to transform into various weapons based on his assigned Prescript. Prior to Ryōshū's departure from the House of Spiders, Rien's left eye was exposed and undamaged. When removed, the mask reveals a scarred part of his face that also has a damaged eye, only showing his pupil from within the wound.
Personality
Rien is a coolheaded individual, acting with grace and simplicity even while harming himself or others. He speaks gently, especially so to Yoshihide, who he shows considerable care for, as far as frequently reminding her to handle her scars so they heal. Though he acts with grace, he carries a sinister air, tormenting people both physically and mentally. Due to his allegiance to the Index, he shows extreme devoutness to orders of the Prescripts, going as far as maiming himself to prove the completion of his orders. Despite his unflappable demeanor, Rien harbors mixed feelings regarding the Prescripts. As it is due to them that he could indulge in sufferings and the pleasures of the City, Rien is thankful for the chance they allow him to enact great violence onto others; however, he conceals a resentment towards them, having harbored a genuine attachment for his previous family, which he had allowed to die by following the order of the Prescripts. Rien also grew attached to his second daughter Ryōshū, to the point that near the end of his life, he was finally willing to defy the Prescript to attempt to convince her to return to her family in the House of Spiders, believing them to be able to protect her from the rest of the Fingers. While Rien returned to following the Prescripts after making his escape from the House, he eventually commits one act of true defiance in refusing to recite a poem that had been assigned to him by a Prescript, and deciding to take his own life instead.