Yes, it is quite popular. The story has a unique concept that combines elements of isekai, comedy, and action. Its protagonist's over - the - top and self - deluded yet somehow endearing personality has attracted a large fan base.
Well, there are themes like the power of perception. The characters in the 'Read the Eminence in Shadow Novel' often misjudge each other. Also, the theme of friendship exists, although it's a bit of an unusual form given the nature of the story. The protagonist has comrades who are unaware of his true self, and yet they are bound together in various adventures.
It's a story that follows the adventures of a character who appears to be an ordinary person on the surface but is actually involved in extraordinary and shadowy affairs in the world of the web novel. It often has elements of mystery, action, and a unique power system.
Some people find Eminence in Shadow manga on dedicated manga websites such as MangaFox or MangaReader. But be careful as some of these sites might not be legal or have reliable content.