Yuuri

Age: Unknown
Gender: male, female, and pan - served as inspiration for Yuri's design, which is intended to only be "slightly boyish"
Origin: Unknown
Species: Human
Height: Presumably under 5'2 (158 cm)
Occupation: Unknown

The protagonist, suffering from amnesia, gets caught up in a debate to find the Gnosia who has infiltrated the interstellar ship D.Q.O.

Yuuri is an original character who was created to represent the "player" character in the adaptation.

In episode 10, Yuuri suddenly becomes a girl, possibly hinting at the ability to choose your gender in the source material.

(Source: Official Site, translated)