This LN is underrated.
Isekai have become a common trope in the Otaku world. Even though being part of over used genre, this LN have managed to stand out in more than one way.
It is overly complicated manga which can be considered it's strongest as well as weakest point, whatever you prefer. It is hard to read for average jolly reader, but once you get a hand of it, it is really a master piece.
Why it is hard to read ?
Lots and Lots of character interacting over multiple scenes. In a way, scene does not always revolve around MC which i think is
good. I had to keep a note on notepad of all the characters while reading it. It also have lot of politics which adds complexity to the story which makes it harder for reader to understand. I loved politics though.
MC is born with 2 reincarnated souls inside him. One is a guy from modern world with lot of knowledge and other is skilled fighter from warring states of Japan. This setting is enough to make him OP like almost all isekai story with bunch of girls revolving around him just because he is NICE, BUT IT IS NOT THE CASE HERE. He is not OP and every girl have proper character development to have a strong relationship.
Each character close to MC is developed perfectly with their own role in the story. Harem does not feel forced or just being their for oppai and since it's nobels and all, he don't have to choose between girls. They are there to compliment MC.
MC used tech from modern world to build and grow his business. It is really good to competent MC like him.
It is an epic world building with lots of adventure, comedy and action.