This manga is one of those "I'll mangafy some random kusoisekai, we'll get easy money"
The artist could have refused this project. His 11 chapter doujin is worth a hundred times more than this series will ever be.
I tried my best to like this, i even tried to read the 2nd chapter but fuck dude it's painful to read. The stigma for being a sage is the wisdom, right? But the author here just implies that "oh MC-kun here is sage because i want him to be OP in magic" ffs the MC doesn't have awareness and he was fucking called a sage? And there are actually 102(currently) people who rated this as 10? I'm not criticizing your taste, it's just this series ain't rational nor logical.
Just want to mention, mamono should be monster, not magic item. Mono is kind of a catchall for people, things, animals etc, but mamono almost always monster/evil creature.