The Eminence in Shadow, Vol. 1 Aizawa Daisuke (2021)

There is only one thing Cid wants to become in this world. It is not a bland protagonist or the final boss, but a mastermind working in the shadows. Now reborn in another world, Cid sets about building the perfect stage for the role he has always dreamed of playing. The problem is that the imaginary adversaries and plot devices he has invented actually exist in this new world, and he is the only one who does not know it.