Hatsuko Shigemori is the older sister of Keiji Shigemori and one half of the Faceless unit. She first appears in volume 10 of the manga as an employee at the Omori clinic. Her primary job, however, is acting as an informant.
Hatsuko Shigemori comes from a family of ten brothers and sisters (including herself and her brother Keiji). As children, her brother and herself were often forgotten by people, even relatives. This would show itself in odd situations, such as people being able to recognise if Hatsuko and Keiji were missing but unable to remember who was missing. Hatsuko and her brother were also able to sense other people's true moods easily and eventually decided to utilise these abilities to their advantage.
Hatsuko has long hair that reaches down the entire length of her back. Her hair is presumably blond, as Yun Kouga does not ink it fully black. Otherwise, she is unremarkable, being of average height and features. When interacting with other characters, her face is expressionless. It is only with Keiji that she expresses her emotions.
Hatsuko is thrifty when it comes to money, criticising Keiji for leaving the hall lights on and buying canned coffee, although she doesn't act unkindly towards him. She also expresses delight at the news that they have a new job offer, and will shortly be receiving more money.
Hatsuko is the only member of Faceless seen interacting with other characters of the manga, and when she does so, her facial expression is blank and much of her dialogue is accompanied by an internal commentary. The conversation she does make is nearly always about the objective, and she nearly never volunteers personal opinions, tending to contribute towards the conversation by asking the other person questions. It is only when Hatsuko returns to the apartment and converses with Keiji, that we see her face finally have expression and her personality come out.
In summary, Hatsuko is business-like and reserved. She is mostly detached and only has emotional bonds with her brother. She also appears to be in charge of whether they take a job or not, a dynamic probably stemming from her status as the older sibling used to taking care of the younger.