She followed an extreme interpretation of her religious beliefs, stating that in order to cut off the past she had to literally cut it off. This unfortunately involved Fina killing with her bare hands anyone that reminded her of the past, including her former boyfriend McBain, and her friend Sandy Aren, who was strangled and her body disposed of under the cover of the celebrations of the Ryvius's party in episodes 10-11. A motive given for her first murder suggests her religious interpretation was a coping mechanism evolved after the fact. However, as Fina found out from Kouji and later Neya, the past will always linger. This and the fact she overhears Kouji declaring that their relationship is over, likely drove Fina into a complete mental breakdown - as if her actions in episode 25 were not indication enough, Fina does not return with the others to the Ryvius in the next episode. In the last episode Kouji, given the honour of deciding the Ryvius' new first destination, chooses to visit the Uranus vicinity because he has some things he wishes to discuss with her.