I Transmigrated, but I’m a Tentacle Monster!

(This book may contain elements some readers dislike, including detailed side-character couples and lifespan differences.) After dying because of my own carelessness, I was ordered by an evil god to work for him. I became a pawn on the gods’ chessboard, but this evil god turned out to be surprisingly decent. He used an isekai transmigration form to turn me into a monster befitting his title as an evil god: a tentacle monster… That’s not necessarily a bad thing. Even as a tentacle monster, I can still complete this evil god’s mission and establish a country in this world. But is it really a good idea to let a Paradox Interactive gamer like me build a nation? Besides that, he gave me another mission: overthrow the gods’ chessboard… That’s all well and good, but this guy never told me how to do it! Also, why was the first person I met after transmigrating a man?!