Death Note, Kiseijuu: Sei no Kakuritsu Recommendations
*Produced by Madhouse.
*Main characters are accompanied by a being that is outside of their ''normal'' world.
*Main characters hide their secret from everyone else.
*People having ''mysterious deaths'', although the causes are different in each show.
Although there are many differences, they are both great if you enjoy series with good quality and dark undertone.
Both animes have a premise, death note being the death note, and parasyte being the parasyte. Both shows have characters that build and develop around this premise. which in turn also creates a thicken plot and interesting set pieces of story.
In both shows the main character stumbles upon a supernatural power and has to hide it from everyone. He uses that power for what he thinks it's good for humanity. He also is accompanied by a cynical supernatural being that comes with that power and he is mostly the only one who can speak to it.
These are dark, psychological shows and have a very similar atmosphere.
I really found my self that i was rewatching Death Note with different Plot. Like
1) Cops are suspected of Light for being **** (censored) , same case for protagonist of Parasyte.
2) Human are being killed in both anime and cops are trying to solve it.
3) Shinigami Ryuk can be seen in terms of Migi (Parasyte, right hand of Shinichi) that no one know but him for both cases.
Both shows have similar dark tones. They have some supernatural element connected to main characters who have to keep it secret.
The same studios. Both characters have something to hide from other people and both feel psychological stress. Same atmosphere and dark tones.