I can't find an insert song... I heard it best in Episode 11 around 21:40 - 23:00. Basically when shuu is on the train. It also comes up in ep 8 around 21:14 and also comes up in 22:44 in ep 10.

I just dled the ost and it doesn't appear to be in there, and I am not talking about the ED either.

Can anyone help me identify it?