VISITOR

is a Japanese light novel series written by Kaori Tachibana, with illustrations by Kazunori Ito and Supervision by Akemi Takeda. The series began publication on January 10, 1999 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Year 2029. An era in which the third energy source "antimatter" after nuclear power and nuclear fusion was put into practical use, and the area of human activity expanded throughout the solar system. An artifact that should not have existed at that time was excavated from the 65 million-year-old strata in the Mongolian desert. At the same time, a huge life form appears near Mars. He swallowed the satellite Phobos, which has an antimatter storage facility, and began to approach the Earth. These two seemingly unrelated incidents were actually the beginning of everything !! And it was a beautiful temporary worker who confronted the crisis of the earth.