Cosette is the most anxious girl you'll ever meet. She's very sensitive and takes everything very seriously. She's only 25, and was sent down to old earth due to her anxiety and severe paranoia stopping her from getting a job. She's one of Marie's closest confidants and trusts Marie the most. Her mind always goes to the darkest places, almost comically so.

For her voice direction, like I said she's very anxious and she chooses her words very carefully. Think someone like Toko Fukawa from Danganronpa, or Kobeni from Chainsaw man.