The Red Imperial Army (レッド帝国軍, Reddo Teikokugun) also known as the RIA (リア, Ria), is a large and vicious army under the command of a great demon known as Shujō Hitoriatari (一人当千主上, Hitoriatari Shujō). The army itself is composed of both humans and demons, humans brought from many feudal lords Shujō forced to obey and demons who Shujō gathered and produced himself. They are known for their cruel ways and most people join them out of fear. Soldiers of the RIA can be recognized by the unique symbol on their body.
The Red Imperial Army is comprised of both normal humans, who wield swords, bows and other, and Demons. This army is undoubtedly the strongest in the feudal world, capable of almost any military ground operation.
The largest part of the Red Imperial Army is composed of different warriors from different feudal lords. They have put their differences aside out of fear, and have joined into one, massive army. All of these are well-trained and very strict, making them very effective on the battlefield. However, they are still human, and most of them are afraid of demons, even when they are on their own sides. The warriors typically wear red samurai armor, and wear katanas and other weapons. They also have the typical symbol tattooed somewhere on their armor and skin.
Some of the humans have been "injected" with demonic energy, making them much more effective, but also more barbaric on the battlefield. They can be recognized by their gray skins and red eyes, and Byakuren refers to them as "The Devoured", possibly due their status of being overtaken by demonic energy. The process of becoming a devoured is very painful, and after that, the victims become mindless killing machines. On the battlefield, they cannot discern foe from friend and are generally feared by both. Shujō laughly refers to them as "his little babies", and enjoys the sight of them killing his own, human warriors.
- The symbol, as well as the name of the Red Imperial Army, are taken from the anime Kurozuka.