He was the head of the Reisen family, and was Miledi's father.
Colt is a middle-aged man with blond hair and stern features.
Colt was taciturn, expressionless, and emotionless. He was mindful only of his family's duty and would not hesitate kill anyone who was against the Holy Church, including his own daughter.
Colt had his daughter Miledi take part in their family's duty of executing people that the Holy Church deemed as criminals for years by pushing them down Reisen Gorge and be eaten by monsters. One day, Colt wanted Miledi to interrogate one of the prisoners named Davy Consman by having her act like a curious child in an attempt to use his empathy to their advantage. This was due to his belief that he was part of an organization that was acting against the church. Miledi, however, failed in getting Davy to talk before he killed himself.
When Colt believed that Miledi was old enough to start learning about royal etiquette, as befitted the future head of a noble family, he assigned a maid named Belle to become her teacher. Colt later grew suspicious after noticing changes to Miledi's personality since Belle was teaching her, and eventually discovered that she was actually a member of the anti-church organization that he was after. As a result, Colt had Belle arrested in front of Miledi, much to her shock. Colt then sternly warned her not to do or say anything that would go against her family's morals, lest she be branded a heretic as well. After having Belle thoroughly tortured, Colt had her thrown down Reisen Gorge to die. Miledi arrived soon after in an attempt to stop him, but was too late. She then jumped down the gorge in order to rescue her, against her father's orders. Despite her efforts, however, she was unable to save her. After returning from the gorge while carrying her former maid's body, Colt demanded Miledi that she dispose of her while calling her (Belle) "trash". Miledi refused and proclaimed that she was sick of her family's morals, and by extension, the world's. Colt then decided to have Miledi executed for her defiance. Miledi, in response, smiled for the first time in her life, much to her father's shock, and dared him to try. Colt, as well as rest of the Reisen family, were all killed by Miledi.
- Miledi Reisen - Colt treated his daughter as though she were a tool to carry out the duty of the Reisen family. He never once showed her loved and held high expectations for her to perform her role as an executioner. After Miledi defied her father in order to save Belta Lievre from death, Colt did not hesitate to have her killed, but was disappointed in having to make such a decision (only due to the fact that Miledi was in possession of Ancient Magic).
- (To Miledi Reisen): "Letting yourself be fooled by a heretic was a serious blunder. Compose yourself, Miledi Reisen. This is your last chance. A Reisen who cannot perform their duty is of no value."
- The word "Reisen" is German for "To travel". It also means "To fall", as well "To rise" in some cases.