Voice Actor: Travis Willingham (https://youtu.be/IPWdAWkozrU?t=7)

Relius is one of the three main antagonists of the series, alongside his partner, Yūki Terumi, and their mistress, Hades Izanami. Relius is Carl and Ada's father. He's a genius alchemist known as the Puppeteer, and revealed in Central Fiction to be formerly a wizard known as One of the Ten Sages, using both magic and science for his inventory. His inventions include the artificial human Hazama and his modifications to Saya's body, both of whom were used to host Terumi and Izanami respectively. He also created the Murakumo Units, which themselves consist of Nu-13, Lambda-11, and Mu-12, and the Nox Nyctores named Deus Machina: Nirvana, which he harvested his daughter's body to create. He completed the latter with help from Kokonoe of Sector Seven, only for his son Carl to steal it and use it against him. His own puppet, the Fluctus Redactum: Ignis, was created from the body of his wife, Ignis, who is similar in appearance to Nirvana. He summons Ignis into battle with his Drive, Detonator. Relius's main goal is to recreate the world to his desires, despising a world where the Master Unit controls everything.

Relius is the twisted, evil mirror image of his son Carl. While he is calculating and courteous like his son, he is cold and utterly devoid of empathy. His only true care in the world is his research. Relius is even willing to go so far as to kill gods for the sake of science – a curiosity which Terumi just so happened to pique. Carl, his son, hates him for taking Ada and his mother away, and spends a majority of his travels in pursuit of Relius. During Noel Vermillion’s story in BlazBlue: Continuum Shift, Relius attempted to kidnap her in order to 'examine' her, and he had gotten a hold of Arakune at the end of his respective story. He did not hesitate to attack his own son when confronted by him.

It is revealed through BlazBlue: Continuum Shift’s Story Mode that part of Relius’ lack of empathy stems from his prior experiments, as well as his experience in the Boundary. During the process of restoring Nirvana, as well as the time he fell into the Kiln, he saw what he believed to be a person’s true form: a ball of bluish-green light which Relius refers to as a person’s soul. From this revelation, Relius began seeing humans as nothing more than “things”, rather than living beings and therefore their existence is meaningless (conveniently excluding himself).