He spends his time locked up in his room practicing, he didn't even kill a zombie until episode 18, it's super slow.... There is also a drama with his neighbor's wife, and there is also some NTR and drama, some green in chapter 18.
The MC literally keeps his neighbor's wife and his neighbor's wife, and gives him food. While they are happy with his life. A disgusting novel, if he does that I can't imagine what will happen to NTR, it is obvious that the author likes to be a flying green turtle.