It is unknown what occupation Kuro had before his Umbral Transformation, nor why he tried to control the forces of Darkness. All that is known is that he was completely engulfed by the shadows, and literally became one himself thus making him Mute. Not long after his transformation, Kuro came across an abused young girl who had also been fused with darkness and began looking after her as an older brother would his baby sister. She soon took on the name Oscurita and they were both discovered by Kagai soon after the Makata Invasion, and became members of The Children of Darkness. He usually hides away with his little sister's shadow, appearing when he is needed to aid Oscurita in combat against more powerful beings.
Kuro is a special case, as his transformation both granted him slight control over darkness, but also imprisoned him for all eternity in the Darkness he wields.
- Shadow-Movement Ability: Kuro can move instantly to new locations, using Shadows and Darkness as a transportation method.
- Manifestation: Although not able to completely leave his Dark prison, Kuro can manifest himself to the point of looking almost human again. However, this usually takes large amounts of energy and requires a large amount of darkness. He usually only Manifests his right eye, which has turned a blood-red colour due to his transformation.
- Tendrils of Darkness: Kuro can shape darkness into razor-sharp tendrils that can impale, capture, strangle, and even tear enemies to pieces with a single thought.
- Demon Eye: Also known as Devil Gaze and The Death Stare by Humans and Mutants, and Mind-Rape by his fellow Umbrals, this evil technique is the strongest in Kuro's arsenal. Although his right eye is completely normal, minus the blood-red Iris, his left eye can somehow cause massive mental breakdowns, or even death, to any being he comes into eye contact with. This ability only works on those who have a great fear about something however. For example, If Kuro locked eyes with Amalgam, the technique would do little, to no damage to her whatsoever due to her fearing nothing. If performed on a being with Arachnophobia, the victim's conscious mind will be sent into a trance-like state, where they imagine themselves being swarmed by millions of spiders at once. They'd feel like an eternity has gone by when a mere second has past, and they could die from their heart stopping.
- The word Kuro is Japanese for black or dark.
- Kuro's Demon Eye ability is based off of the Mangekyō Sharingan technique from Naruto