Who is Maniac (a.k.a. Killer, Murderer, Strangler) from Without Feathers and what is their importance?

The maniac is the person responsible for the string of murders throughout the city. He doesn't kill out of desire, nor does he enjoy killing. The maniac kills simply, because he is the killer. He must kill. This sort of circular logic, coupled here as it is with violence, defines a triumph of the irrational.