Kurokiri Setsuna is one of the Shikyou and the leader of the Ayakashi. He is also the one who killed Blue's mom. She is the reason that he lost his right eye.
Kurokiri has an eyepatch and wears a hat. He has pointed ears and long stringy black hair. He also wears a gloves, a long sleeve red shirt, a scaf, and a cloak like jacket.

The fifteen-year-old protagonist of the story, Rin is the son of Satan born from a human woman and is the inheritor of Satan's powers. His powers were sealed at birth into the demon-slaying blade Kurikara by Mephisto Pheles the True Cross Academy principal, allowing him to live a normal human life for about 15 years. Rin became aware of his true identity after Kurikara could no longer seal the blue flames he inherited from Satan, setting off a chain of events that led to the death of Shiro at the hands of Satan, who attempted to drag Rin back to the demon realm, Gehenna. Mephisto Pheles confronted Rin after Shiro's funeral with several exorcists, giving Rin the option to kill them all or die. Rin instead demanded to become an exorcist, an idea that amused Mephisto. Rin was then enrolled personally by Mephisto into the True Cross Academy, where he has since been pursuing his goal to become a Paladin and to defeat Satan. He is currently an Exwire and attempting to gain the title of Meister as a "Knight". Rin can control incredibly destructive bright blue flames, the trademark sign of anything related to Satan. However, when he draws Kurikara, the magnitude of the flames dramatically increases and often leads to Rin being "consumed" by his own flames and losing his mind. Rin also has a Cat Sith, Kuro, who was initially Shiro's, as his familiar. Rin has been shown to have a talent for cooking, notably due to the fact that he had started cooking at the young age of 6.

Rai is a very elegant, and mysterious Noble. He has no knowledge whatsoever of the 21st century, and will often become lost and confused especially with regards to modern day technology (such as using a cell phone). He is often used as the manhwa's comic relief with his love of ramen and the errors he makes with technology. He has fallen into a deep slumber for 820 years, and had woken up in an abandoned building in South Korea. After seeing what most of the humans on the streets were wearing, Rai took on the uniform of a student from Ye Ran High School, which is under the administration of Frankenstein, and inadvertently followed the students there.

While traveling and searching for the remnants of Gwi, he meets a girl who also bears the same mark crossed out than he has. A fateful encounter? Were those two fated to meet? And why does he hold such a grudge against the “Gwi”? ... all are questions left to be answered!

Mu-Sang + Raizel