Much about Kodama's origins are unknown, only that he was adopted by Gulm and can't speak. Kodama serves Gulm, carrying out their orders and protecting them from harm. He's highly skilled in martial arts and his abilities can rival a Makai Priest or Makai Knight. While not a Makai Knight, he has his own armor, a Demon Beast Armor which granted him title Demon Beast Armor Kodama (魔獣装甲コダマ, Majū Sōkō Kodama) along with abilities to rival an armored Makai Knight.
- Light Bullet (光弾, Hikaridama): Although Kodama doesn't speak, he does have a magical voice. By concentrating his sonic energies into his hand, he can create explosive blue orb-like Light Bullet. The louder his voice, the more powerful the orbs become. He can even create a series of them, line them up, and time release them on his command.
- Demon Beast Armor: As a contingency plan should their accidental pawn Rei aka. Zero eventually realized the truth behind his loved ones' death and had to assist Barago in combat, Kodama and Gulm crafted their respective Demon Beast Armors where his designed like a Horror-like knight which eyes can blink and open its mouth like a real thing. The armor is summoned through deploying several light bullets into a dimensional rift through which the armor equips him.
- Sword: The armor comes with a sword through which he can channel his sonic wave to increase its blows.
- His name is derived from the Japanese word meaning "echo".
- In the Garo Side Story, you finally see him speak; unfortunately, he talks extremely loud and fast in English, which Kaoru mistakes for a Kansai dialect.
- In data book Garo Pia, his armored form is described as Kodama (Demon Beast Armor) (コダマ (魔獣装甲), Kodama (Majū Sōkō)).