Kobayashi Mariko is one of the new and exclusive characters in Fushigi Yuugi Genbu Kaiden Gaiden:Kagami no Miko, and also the main character of the video game. She is aided and accompanied by the priestess of Genbu and the warriors to help her search for her friend who was whisked away in The Universe of the Four gods along with her through a mirror.
Unlike Takiko, Mariko is quite normal, and gives off a more usual and fresh impression: she comes along in a very natural way. Quite mature, she knows how to accept everything; she is aware of her capabilities and faults all the time. Mariko is somewhat attached to her new friends, to the point of relying on them to save her lost friend. She is rather quite patient but at some times she has a tendency to over-react when she doesn't realize the current situation properly. Apart from her eloquent mental state Mariko is sunny, bright, and optimistic, even in the worst of problems. During the routes with everyone she always shows that she is a very caring girl; not only with her best friend Takumi, but also with the people present in whatever case.
Mariko wears a typical designed Japanese uniform, but with sophisticated shades which consists of a white button-down shirt worn under a yellow long-sleeved jacket. A red tie is seen, similar to Takumi's. Her brown skirt is extremely short [ Takiko has noted it somewhere in the game ], exposing more than majority of her legs. Just below her knees dark-purple socks extend down freely until her school shoes.
Her facial features consist of chest-length golden-brown hair that shines and wide eyes that match. Her hair is always seen in a pig-tail style; and its shade compliments her pale skin.
The game's story starts off in the real world when Mariko leaves her house with her friend Takumi after a heated argument with her mother. The two friends go together to an antique shoppe, and this is where they find the mirror and are whisked away soon enough. When they arrive inside the book, Takumi is captured immediately while Shigi and Shura appear in the scene, after the warriors and Takiko are introduced.
Hikitsu (or any male character) will eventually reveal that the mirror's power will be lost in ten days and that Mariko has to save Takumi and get out of the world before the period ends. Respectively, no matter what route the player chooses, Mariko will see Takumi again soon enough; but not as the Takumi she knew but as a Kodoku-poisoned Takumi.
Within the ten-day-period, Mariko's friend Takumi will be the center of a very drastic and decisive fight for life. After the cult is dealt with later, Mariko will be forced to go back to her world with Takumi.