She is among the most enigmatic of the horror elements of OMORI, as it is unclear what her purpose exactly is. She mostly appears to scare OMORI and SUNNY, as well as appearing where MARI would usually be. It is unknown exactly what HELLMARI is, but it is most likely a form of SOMETHING, taking on the form of MARI when she was hanging from the jump rope, albeit heavily distorted and warped to the point of being unrecognizable as MARI. When she touches OMORI, however, her face will warp into a similar gaping-mouth expression to the other versions of HELLMARI and the colors of her sprite will become much more saturated. She has an elongated neck and she appears to be smiling. She has a normal color scheme which matches that of the real MARI. This version of HELLMARI appears in BLACK SPACE, mostly in the RED MAZE and MIRROR AREA.
Her head bears a heavy resemblance to the blue HELLMARI, but she has less hair that is more stringy and rows of sharp teeth can be seen inside her mouth. Unlike the HELLMARI that appears in SUNNY'S HOUSE and RED SPACE, only her head is seen and she has a monochromatic color scheme. This version of HELLMARI mostly appears in BLACK SPACE. She is wearing a white dress, similar to the one MARI's spirit wears and what MARI was wearing when she was hung from the tree. Her head is bent at a sharp angle and resembles a person's broken neck after they are hung. Her head appears elongated and skull-shaped, and she has long, stringy black hair that extends past her visible sprite. She has a large, gaping mouth, and her eyes are replaced with empty sockets she lacks a nose as well. The version of HELLMARI that appears in SUNNY'S HOUSE and RED SPACE is tinted blue, likely due to it being nighttime whenever she appears in these areas. Like many other horror elements of the game, she appears much more realistic than most of the game's contents, likely to scare the player more due to how out-of-place she looks. There are three versions of HELLMARI that appear in different locations throughout OMORI.