That anime is such a wasted oppostunity. Nice characters and ideas, awesome villain, possibly one of the best anime villains of all time. But the plot is all over the place, feels so arbitrary. And after the villain reveal in the middle he becomes the main character essentially and takes too much screen time.
The song at the end ... Niji no Kanata was one of the first Japanese songs i learnt, emotional moment when i realised i still remember the lyrics 16-17 years later