Twin King of Kazdel. Theresa's twin brother. A handsome man with black horns rising from his head, pointed ears, and black earrings. He wears heavy metal armor and a tattered red cloak. A swordsman. He is calm and composed. He trusts Theresa deeply. Sarkaz. Red eyes. He wears his short pink hair slicked back. Contrary to his blunt way of speaking, he respects and cherishes Theresa very much, and he grieved deeply when the Amiya of this world died.

Twin King of Kazdel. Theresis's twin sister. Long, flowing pink hair and black horns rising from her head. A beautiful woman with red eyes. She has a loving personality, full of emotion, benevolence, and playfulness. She cherished Amiya dearly and cried in deep sorrow when she died. Sarkaz. She wears a long white dress and black boots.

The Demon King of a parallel world. The Finale of the Core. Judging that there is no hope in the Terra of the parallel world, she wanders from place to place, covering the land with Originium for the sake of Terra's humanity. A girl with long rabbit ears, brown hair, and blue eyes, characteristic of a Cautus. She wears only a single, tattered white dress. Black Originium crystals sprout all over her body, and her face is covered by a black veil. Originium crystals resembling a crown float around her head. The Amiya of this world died of Oripathy and is a painful memory for Theresis and Theresa. The Demon King Amiya from the parallel world descended to protect them by preventing them from leaving Terra. Although she has the appearance of a young girl, her entire body has been replaced by Originium, granting her eternal life. She can float in the air.