Yume

Appearing a time ago in the story, Yume looms ominously as one of the most serious threats to yet be unaccounted-for.

Bio
Revealed to be the creator of The Shima Brothers, after Mushima's death, Hishima and Takashima succeeded in unsealing Yume from her self-imposed stasis within a hidden Royal Tree. Clad in nothing at all, she emerged and proceeded to backhand Hishima with savage force - Admonishing her creations for being "7,200 hours later than planned."

Though F-Klak seemed to show some interest in her, Yume's present whereabouts are unknown. For the time being, she seems to be waiting for an unknown opportunity to reveal herself.

Abilities
Great Strength: Despite her small size and slender build, a single backhand shortly after emerging from uncountable years of stasis was able to send a largely-mechanical being the size of Hishima flying through the air.

Great Agility: Yume has displayed great speed, very nearly catching Hishima with a surprise hit - Hishima being the apparent fastest of his brothers.

Swordsmanship: Though not shown in great detail, Yume seems to at the very least have surety while handling a sword of high calibre.

Genius Intellect: It has been all but confirmed that every single piece of technology used to harness The Arboretum Notes and the Royal Tree was built by Yume herself.

Trivia

 * Yume's name means "dreaming" in Japanese.