Koumori, also known as the Master Spirit of Darkness and The Shadow, is a guardian spirit and the Master Spirit of darkness. He is a bat and was chosen by Azmyth to be the keeper of the element of darkness.
Koumori is smaller than average guardian spirits and is covered in dark brown fur. His wings are a tan color and he wears silver armor on his head, back, chest and feet. His left eye has a vicious scar over it and he has several piercings on his wings.
Koumori is very sneaky and prefers stealth over straight forward attacks. He is still quite young and therefore, rather immature, but is able to get along well with other guardian spirits.
As a spirit of darkness, Koumori has power over and is capable of manipulating all elements of darkness.
- Shadow Echo: This gives Koumori full immunity from physical attacks and nearly impossible to capture on tape. He is able to escape by turning into a shadow.
- Shadow Scratch (Offensive): Dives into the ground as a shadow, moves up to the opponent and slashes them quickly before diving back into the ground.
- Dark Maiden (Offensive): Koumori surrounds his foe with darkness and strikes from multiple positions with great speed.
- Shadow Split (Defensive): Koumori splits into four illusion copies.
- Shade Screech (Offensive): Partly used for Koumori's vision. The other purpose is for stun the opponent with a piercing cry.
When combining himself with any type of weapon, Koumori becomes a two-handed axe, called the Shadow Axe. It is capable of splitting in half into two one-handed axes.
When combined with a human, Koumori's Beast Fusion form is called Moonlight Echo and appears to be a ninja. The human will be covered in Japanese-style armor with two hook-like weapons on the right wrist. He/she wears a half mask, bearing Koumori's facial scar and a long white scarf that turns into a giant pair of bat wings.
- Koumori's name is Japanese for bat.
- Koumori was inspired by the novel Silverwing by Kenneth Oppel.