Hellnight, or Dark Messiah (ダークメサイア) in Japan, is a first-person survival horror video game developed and published by Atlus in 1998.
The future Tokyo is a megapolis built on top of a huge system of underground tunnels and sewers. This underground world hide the followers of a mysterious cult, known as the Dark Messiah. At the same time a symbiotic life form escapes from a research station and makes it's way into the sewer system, causing the crash of a subway train and starts devouring the passengers on board.
Only the nameless protagonist, and a schoolgirl named Naomi Sugiura survive the crash and subsequent attack of their train. Together, they decide to flee from the creature and into the sewers.
The game consists of mazelike maps, there is no combat. The player must travel through the underground and protect Naomi. There is only one monster in the whole game, which cannot be killed. Hellnight can be seen as a modern takes on 3D Monster Maze and a precursor to games like White Day and Amnesia: The Dark Descent.
The game's atmosphere relies on alternating between the puzzles and solutions in certain rooms and the dangerous legwork between each point of safety where the creature roams.