Kokuyou

Kuroyou (黒曜 Kuroyou, literally meaning "Obsidian") and Sango (珊瑚 Sango, literally meaning "Coral") formerly known as The Genbu (玄武, Genbu) are a companion and contracted beast of Touya on his journey. They are one of the Four Divine Beasts and also the leader of the Scaled Creature.

Appearance
Kuroyou and Sango's true form are a large jet black serpent as big as an anaconda with a pair of golden eyes and a 4-meter-high tortoise. After Kohaku told them about the trouble that they might cost because of their form, they then changed their appearance in similar way to the Kohaku's form.

History
The Genbu (玄武, Genbu) which later known as, Kuroyou and Sango, are one of the divine beast that can manifest in the world once every few decades or centuries, unless they are being summoned by human.

Abilities

 * Intimidation Aura: They are able to release suppressing aura that render all individual, which have lower magic level in respect to the divine beast, becomes immobile.
 * Long-Ranged Telepathic Communication: They are able to make telepathic communication with their master and among the divine beasts regardless the distance. They also able to include other people into this communication line.
 * Form Transformation: They are able to change her menacing true form appearance into cute young beast form (Child Form) and back as they pleased.
 * Floating: When in their Child Form, they can float in the air while reducing their speed.
 * Magic Barrier: They have magic barrier that is able to repel all type of physical attack completely and also all type of magical attack with respect of the caster magic level.

Trivia

 * According to the character introduction, even though Kuroyou is a male, in heart he is a female.