The Woobie: Pretty much every single character is this in some way.
Kelvin is forced to confront his late wife, and the guilt of the role he took on her suicide. Then he has a more direct role in a second "death" and has to confront her again, then he tries to protect her from the other humans knowing that even in the best outcomes he wouldn't be really able to have a happy fulfilling life with her.
It is implied that the other three humans have been put through similar emotional turmoil for considerably longer and are devastated by it. Snow and Sartorius are Jerkass Woobie, the former seems to have indulged in the company of his visitor but still ended up an alcoholic wreck, who has "killed" them more than once. The latter looks deteriorated and acts anxious and shaky, both are understandably paranoid a lot of the time. Gibarian was outright Driven to Suicide.
As Rheya spends more time existing she starts to realize her condition, which plunges her into an existential crisis not understanding even what she is. She ends up killing herself. Twice.
