For centuries, the world of Erathia has been devastated by a war between humans and demons. To make matters worse, the king of the humans is being held prisoner by the demon armies. A young warrior named Ewan is sent to find the king by a mysterious nobleman named Mendes. On his way Ewan encounters Lorean, an elf archer, who helps him on his quest. Kayn, the captain of a group of mercenaries called the Unicorns, later appears and assists them in freeing the king.
The three then set out to kill the demon lord, who escapes after a fight with Ewan. The demon lord is confronted by Kayn; he attempts to make Kayn defect to the demons since the latter is a half-demon, but he reveals that he is not on the humans' side either; he says they are only his "tools". Ewan and Lorean overhear this and leave.
Mendes plans to reveal that Kayn is a half-demon so he will be able to become the king's right-hand man. Kayn overhears this and tells Ewan to meet him at the king's castle. He tells Ewan that Mendes is trying to prevent the return of the king, and has to be killed. Kayn confronts Mendes and kills him; a knight then attacks him and is also killed. Ewan refuses to help Kayn any further and the two get into a fight. They depart, and Kayn is arrested for killing Mendes. A year later, Lorean asks Ewan to help her rescue Kayn, and he agrees. They find Kayn heavily wounded; the demon lord appears and takes Kayn away. Ewan finds them and kills the demon lord and a three-headed dragon. Kayn apologizes for his actions. With the demons defeated, the humans start rebuilding Erathia.
