When Ibiki tried to torture one of the six paths of pein, why doesn't she(?) feel the pain? Isn't the pein a living being?
When Ibiki tortured the Animal Path, he realized his techniques were not working
Ibiki attempted to torture and interrogate the Animal Path, but soon realised that it was unable to feel pain, and seemed to be cold like a corpse.
because the real Pain is the only one that is living. The different paths are all corpses and controlled though the black roads that are in them
Nagato created the Six Paths of Pain out of corpses that he controlled remotely