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NPC Info
Role None
Location Mars: Martian Underground
Size Huge
Killable? No

Mars-san (火星さん, also known as Tasei-san, Kasei-san or just The Martian), is a decorative NPC found underground on Mars.


Mars-san is a tall, indigo creature with a single large eye and a single foot, interpreted to be some sort of alien. Green and red dots also cover its body alongside faint green streaks. Its eye has a red sclera and a bright pink pupil. Near its eye is a light green opening, which some interpret to be a wound, that slowly leaks red drops with green outlines. It is found near what appears to be a crashed locomotive all by itself while a depressing piano tune plays.

When interacted with, Mars-san produces a remorseful three-tone chime (high B flat - E flat - F), coupled with a small darkening of the screen. When stabbed with the Knife effect, a red cut appears on its foot and its eye will change colors. After stabbing it, its sclera will turn green and its pupil will turn blue. Stabbing it again will revert the eye color back to normal, though the wound will remain until Madotsuki re-enters the room. It does not react to any other effects.

In the manga

Mars-san in the manga.

In the Yume Nikki manga, Mars-san appears to be an authority figure in the dream world, speaking in a robotic tone like a supercomputer or security system. They are considered Seccom Masada-sensei's boss and help form the dream world with him.

Mars-san's presence is first made apparent through a scrawled message in Madotsuki's dream diary, which orders her to collect the effects hidden around the dream world. However, Madotsuki decides against searching for the effects, writing that she will not do so under the message. This alerts Mars-san as the machinery next to it begins to burn, making it announce that a system failure is imminent. Mars-san also reveals that Madotsuki is one of six dreamers that have created the dream world.

Later into the story, Poniko approaches Mars-san to see what she can do to stop Madotsuki, who has begun killing the dream world's inhabitants. Mars-san deems Poniko worthy of the task and gives her a Knife effect, which it reveals is a super powerful tool that can destroy anything in the dream world.


  • Some fans consider the creature that is sometimes seen in the pond on the Witch's Island to be the child of Mars-san due to their shared likeness.
  • Mars-san bears a resemblance to the 1926 surrealist painting "Person Throwing a Stone at a Bird" by Joan Miró. Other characters also resemble famous surrealist paintings, such as Tokuto-kun and FACE.
  • The name of the creator of the game, KIKIYAMA (ききやま), can be translated as "machine mountain", with "KIKI" (機器) meaning machine/equipment, and "YAMA" (山) meaning mountain/hill. This could possibly allude to Mars-san, as they are located underneath a mountain on Mars and are seen next to a machine-like object.
    • Due to this connection, some have speculated that Mars-san is a representation of KIKIYAMA themself.


Some fans have interpreted Mars-san as representing Madotsuki herself, as it is all by itself in an isolated location and weeping (although Madotsuki's state of mind can be vastly debated). Mars-san's isolation could be a representation of Madotsuki's own reclusiveness, as she always remains in her room in the real world, or a literal or mental symbolism for feeling "trapped", as Mars-san is clearly too big to leave its room itself due to the only exit being a small hole.

The fact that Madotsuki must fall asleep in three different beds in order to reach Mars-san could mean that they represent a repressed memory in Madotsuki's subconscious, as Madotsuki would be dreaming in a dream in a dream, leading to a deeper part of her mind.

Mars-san may also heavily connect to the traffic accident theory: the machinery next to Mars-san and its tears could represent a crashed vehicle and Madotsuki's possible remorse from losing someone close to her in some sort of accident. The green mark in which it produces tears could also be interpreted as a bleeding scar, which could both symbolize a physical injury from a hypothetical accident and a psychological scar from experiencing a vehicle crash, especially in the case of another dying during such an event. It should also be noted that the only way to reach Mars, and by extension, Mars-san, is through the Spaceship itself crashing. Additionally, the sclera of Mars-san's eye comes in bright red and green colors (the latter when stabbed with the Knife effect), which could link it to stoplights/the Stoplight effect.