Translations:Codex: Sionach/11/en

Complex organs inside of the Sionach's torso produce a strange chemical mixture that becomes luminescent several seconds after being exposed to oxygen, creating a ghostly looking flame. This “firegas” is completely harmless, being a biological phosphorescence - essentially, it's nothing more than glowing mist, being tasteless, odourless, and having very little heat. It is believed to have evolved as a method for warding off predators, much like a leithan's bio-luminescent plating.