What is mato seihei no slave?

"Mato Seihei no Slave" is a Japanese manga series that was written and illustrated by Nagatsuki Miyuki. The manga was serialized in the Comic Alive magazine by Media Factory from March 2018 to December 2019. It was later collected and published into six volumes by the same publisher.

The story follows the life of a young boy named Yuu who lives in a world where humans and monsters coexist. Yuu provides a valuable service as a "slave" for a powerful monster named Glanz. Glanz is one of the strongest monsters in the world, and Yuu is tasked with protecting Glanz from any harm. However, instead of being a mere servant, Yuu wishes to become Glanz's "Knight" and fight alongside him as an equal.

The manga is heavily focused on the bond between Yuu and Glanz, as well as the conflicts caused by the coexistence of humans and monsters. It also includes themes of friendship, loyalty, and finding one's place in the world.

"Mato Seihei no Slave" was well-received by readers in Japan and has been licensed for an English release by Yen Press. It is also being adapted into an anime series, which is scheduled to premiere in 2021.