The Demon King is a being which appears on the earth shortly after the dragons. The dragons first appeared on earth in order to prepare for the very coming of the Demon King, but with the misunderstandings the humans quickly made that plan was ruined and the Demon King appeared and could feast on the humans with ease. It appears in both chapters and is able to grow stronger quickly simply by feeding on the fear humans have. It was defeated by Carmine and Riko in the first chapter with a little help from Sagara, one of the humans who used to detest dragons a great deal. After Carmine and Riko begin to approach it it grows stronger because Riko gets afraid of it, but carmine gets her back to her senses. Then Riko slowly begins to see her own self in the image of the Demon King because she to wished for the worlds destruction at one point. This makes her stand up courageously and leap off of Carmine and destroys the Demon King with the help of Carmines horn she was given. However she is greatly injured from the ordeal and as a dieing wish makes Carmine promise to protect the beautiful sky forever after she is gone. Carmine stays true to his promise and over 200 years later lives atop a giant tower. After many events and meeting Rulishia the demons along with the Demon King slowly begin to reveal themselves again and again Carmine must go off and fight, leaving Rulishia behind. It is unclear what happens afterward as the anime was never completely finished. The Demon King itself is a giant black creature with glowing yellow eyes and what look like giant black wings and root like body embedded in the earth. Carmine also once said that demons and the Demon King are fearful of dragons horns, this shown true when Riko used it to swat away demons that flew towards them when they approached the King.