Reincarnated as a Slave

A graduate student traveled through parallel time and space and came to a strange world, where the male protagonist's consciousness was attached to the body of a slave. In this strange world, the protagonist does not have invincible plug-ins and systems, and his only golden finger is the knowledge in his head. Use knowledge to survive in this strange world, and also use knowledge to help others. A person's life is lonely, but the consciousness of the original owner of the body has not disappeared. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.