Although he makes no appearances in the anime, he often will speak to Orion, and talk through Ukyo. In Amnesia: Later, he appears and looks similar to Orion, yet older. In spirit form he has large horns, silvery blue hair that is parted in the center, blue eyes; in human form he wears casual clothes and has no horns.
Neil granted Ukyo's wish to allow him and his girlfriend, the Heroine to go through parallel worlds in his attempt to save her from her death that occurred on August 25th. If she is able to survive until after the 25th, Ukyo's wish would be granted and they will be able to be together in their world, but many of the times that Ukyo attempted this, either the heroine or himself had to die. Due to this wish, Neil and Ukyo's spirits are intertwined, similarly to that of the Heroine and Orion's connection. The Heroine died in a fire at their university. As the Heroine went through different world's, Ukyo followed her, to make sure she was safe, they eventually reached their original world. As it was the world she originally died in, it constantly tried to seal her death. They eventually both survived and Ukyo's wish was granted, thus allowing them to be together, and releasing both Orion and Neil from themselves.
Granting human's wishes.
Part of Ukyo's (Joker) conscious, king of the spirit world.