Kurogane Communication

The Earth has been deserted. The human race has been wiped out. Robots now inhabit it . However, one human remains. A young girl named Haruka is the last human left on Earth. With the help of 5 robot friends, she will find out how the Earth became a place for robots, and her own past.

(Source: MU)

Included one-shot:
Volume 1: Trouble Robomaru