Finn is a mouse, and infrequent guest inside Cee's head. She likes to visit the bird Viktor, fascinated by all that plagues him. They spend entire evenings together, talking about the future and the science of bread.
It is said that after Finn was hit by lightning, her tail split in two and she became immortal. No one if this is true, but Finn makes a point of mentionning it everytime she visits. Finn is inquisitive, wise and has some strange ideas about life, which Viktor and her argue about for hours, over cups of peppermint tea.