Hyakuren no Haou to Seiyaku no Ikusa Otome

Briefly about Hyakuren no Haou to Seiyaku no Ikusa Otome manga:

A modern middle school student called Suou Yuuto, ends up in another world called “Yggdrasil”, right in the middle of war. In a world ruled by the survival of the fittest, in which the many clans fight for the hegemony, Yuuto rose up as the “Wolf”clan patriarch with only 16 years old, leading thousands of soldiers using his modern world knowledge as a weapon.