Salaryman ga Isekai ni Ittara Shitennou ni Natta Hanashi

The main characters in both series are summoned to another world to solve problems on behalf of their summoners' countries Both mc rely on their rational and practical knowledge and skill of the modern world to overcome challenges and build relationships with other characters 

Two fantasy adventure comedies featuring a human joining the demon lord's army as an important person within, Yuuyame's MC helping solving issues for the army and each general whereas Salaryman's MC being assigned one of the four generals solving issues too. Their premises are very different in that Yuuyame's MC is overpowered and has the power to defeat the demon lord but decides to quit being a hero and join them instead whereas Salaryman's MC was isekai'd to the high fantasy world and is a completely normal human being with no much superpower except just recalling his past skills as an employee to use in negotiations and business strategizing. Within both, we see the MC's make positive changes to the demon army and slowly become more well-liked by the people around them. read more