Demon heart

Kazuko is a young half-demon prince, his father the demon king has decided to name his only son king, his intentions being, he wishes to see his son rein. Due to Demons living for hundreds of years the demon king wants to step down from the throne, so that his son can reign, Kazuko being half-demon means he only lives as long as a human, he will live and die before his father even grows old. Not wanting to become king yet, Kazuko runs away from his kingdoms safety, following the tales in his mother's old lullaby's.

Irenie is the youngest daughter to king raygas, she is also the only surviving child to said king and is therefore his only heir, in an attempt to escape her fathers cold and ruthless reign, she runs away in hopes of finding a way to end the long lasting hatred between demons and humans. Iree had been on the run for a week when she ran into a boy, who's eyes held the kindness and warmth she had been longing to find, the only problem was, he was a demon. A fight broke out between the two, both unsure exactly what the other's intentions were, eventually they came to an understanding after Kazuko had shown her he was indeed everything but what her father had told her, he was kind and wished for a world of piece, a world just like the one she wished for.
The two traveled together for a while, no destination set, not knowing exactly where they were going, but just the same enjoying each other's company. One evening while out looking for firewood, iree happens upon a snake demon he had been caught in a hunters trap. He had clearly lost a lot of blood and was beginning to weaken due too it. Iree who had come to realise due to spending so much time with Kazuko, that not all demons were as bad as she had thought them to be helped him, unknown to her the three of them world soon be the ones to save their kingdom.