What are the main characters in "There Will Come Soft Rains" by Ray Bradbury?

The story "There Will Come Soft Rains" from Ray Bradbury’s
The Martian Chronicles has no human characters. The concept behind
the story is that all human life on Earth is gone, but this fully automated house keeps
going because it is a machine. We know people existed at one point because their
outlines are visible outside.

The house is really the main
character in the story, and is supposed to be a machine, but Bradbury gives the house
human-like qualities (personification). The robotic mice in the story are described as
angry and at the end of the story when the house catches on fire, the house is described
as “dying” and screaming. The story says the house “tried to save itself” showing a
human desire for self-preservation.

The other short stories
in the collection have human characters, but the house would be the main character in
“There Will Come Soft Rains”.