Cambria Bakuhatsu Tarou

Yuta, a boy transported to another world along with his classmates, finds himself in a realm where earthlings are summoned for their high inherent power. These powers are used to operate humanoid machines known as magic-machines through a special ability called Ludia that resides within humans. However, Yuta’s Ludia value is shockingly low, with a reading of just 2. While his classmates are auctioned off at high prices, Yuta is sold at the lowest price and becomes a slave. But an encounter with the white magic-machine, Arleo, might just change his destiny. From being an unwanted slave to becoming the strongest hero who shakes the world!

From Bookwalker: A billion years ago, there was a super-ancient civilization. The ancient civilization that possessed high technology became instinctive due to a terrifying plan led by a genius scientist. How did the man grow up to be someone to destroy the world? A spin-off manga that explains the birth of KAIJUs in "GAMERA -Rebirth-."