Ruby Karma is the reincarnation of Emery Almond, who was a close friend of Miwa Hino’s mother and Miwa’s own best friend. As such, Ruby bears an identical physical appearance to Emery.

She serves as the core of Wadatsumijima, having been reborn during the Fourth Operation Azure after Emery Almond vanished alongside Yumiko Hino, their lives returned to the Mir. Ruby then appeared before Miwa Hino.

Following the failed Fifth Operation Azure, Ruby responded to Dylan Basel’s detection of an immense power by asserting that preparation for the future was necessary. She told Miwa Hino not to be sad, declaring that hope would never disappear.

Three years later, when the expeditionary force returned to Wadatsumijima with Soushi Minashiro, Ruby advised Dylan Basel that Soushi must be welcomed for the sake of their desired future, despite any distrust. She welcomed Miwa back and informed Soushi Minashiro that they had both gained life on the same day—a claim he initially dismissed.

Observing a crystal turning red, Ruby instructed the pilots to board their Fafners, interpreting Soushi Minashiro’s intent to destroy the island with the Mark Nicht as a trial they must overcome.

Ruby Karma acts as a spiritual supporter and often preaches on philosophical concepts she describes as "the horizon of existence and nothingness" and the "possibility" lying beyond it.