The Master of Ragnarok & Blesser of Einherjar

"The Master of Ragnarok & Blesser of Einherjar" (Japanese: 百錬の覇王と聖約の戦乙女, Hyakuren no Haō to Seiyaku no Varukyuria) is a Japanese light novel series written by Seiichi Takayama and illustrated by Yukisan. The story follows Yuuto Suoh, who gets transported to a world resembling Norse mythology while testing an urban legend. Armed with modern knowledge and his smartphone, he becomes the patriarch of the Wolf Clan and embarks on adventures with a group of Valkyrie-like warrior maidens known as Einherjar. In addition to the light novels, there is a manga adaptation illustrated by Chany, which has been serialized on Hobby Japan's website since 2015, as well as an anime adaptation by EMT Squared that aired in 2018. The narrative focuses on how Yuuto uses his modern knowledge to navigate a world of ancient wars and magic, striving to survive, develop his power, and ultimately reunite with his childhood friend and love interest. He utilizes his smartphone for knowledge, implementing advancements in agriculture, military strategy, and technology. His leadership abilities, coupled with his humble nature, earn him the loyalty of many."