Now I have not got enough time to give you the full run down on these two series but they are basically two very old manga/anime (they make dragon ball look young) that are very well know in japan and have cult followings in the west. Both have had multiple manga series and anime and these ova's were a cross over. They are both very good works (I cannot say if you'll like them or not as I can't read minds) although Devilman should not be read/watched by anyone younger then 18 or of a weak constitution.
Anyway during the story an evil scientist is creating a new batch of next gen cyborgs but he wants to push things to the next level and create a cyborg/demon hybrid. His Cyborg 0018/Set a young white haired boy who possess a lot of power including psychic abilities, regeneration and acceleration (activational super speed) but who also has a very weak and kind personality.
And the demon he's going to be fusing with is the demon hero Atun.
He's a powerful demon who rivals Devilman and in the manner of his kind has many powers and abilities at his disposal. Although he primarily uses dark electrical attacks.
Well they fuse but in Devilman when a demon fuses with you they get to keep your body plus its new power unless you have the strength of will to resist them. At first Atun takes full control but after the heroes find a way to shut down his regeneration somehow he turns into a being calling himself Azazel.
He describes himself as being beyond such terms as Demon or Cyborg and when his body is analysed he is described as being in a tenuous state of balance. He also calls down lightning from the sky to one shot everyone.
Now I cannot be the only one to see the resemblance here can I?
