As Paz mentioned above, that's also Sumireko. Her outside world self, sleeping, and her mind entering Gensokyo on the right. The left side shows her normal life which is bleak because she has no friends. Although it was intentional of her, it doesn't change the fact that her life could've been better. The right side shows her soul going into Gensokyo whenever she sleeps, and it is pictured as a pleasant light because in there, she finally made some friends.
I think this further supports the theory that Sumireko is supposed to represent the Touhou fans that dream of going to Gensokyo. Those who find pleasure while indulging in the fantasy and lore as a way to enjoy their otherwise not so satisfying normal life.
