This is the fourth volume of the S. Korean light novel series that is also a manhwa (S. Korean comic-manga).
This 4th. Volume has about 50-75 pages less than the first three volumes, it seems the author is reaching a conclusion to his original main plot arc. All of the volumes have 10 chapters each, so far. Positive, Jinwoo, main character is finally healed his mother's coma. Finally worried about his family. Since main character basically trains and tries to become more powerful, everything else is not important and discarded almost to a sociopathic level.
Four observations: 1) New skill shadow exchange, when main character, Jinwoo, used it, he "teleported" or switched places with a Knight that was stationed at his home building. But then why on Earth would the knight stay where he was (Demon Lord King's Castle)? Yes, they switch places, but author doesn't explain or doesn't recall the knight Jinwoo left stranded at the Demon King's Castle. 2) Strategy for ants in Jeju Island, used an EMP (Electromagnetic pulse) But Ants, are biological. There are no electrical parts to ants, so an EMP, would not work where there are no electric parts and components using electricity. 3) Jinwoo has six doses of the miracle life-restoring elixir of life and yet, the first thing that he came up with Byunggu was to raise him as an undead and then release him. Jinwoo did not use an elixir of life on S-Rank Cha Haein from S. Korea. The girl he had met at the A-Rank Dungeon belonging to the Hunter's Guild. Unless Jinwoo summoned (as a necromancer) Byunggu (because he was a healer when he was alive) (to cure Haein and then released him as a death summonee. 4) Because all of the main plot arcs closed here on volume 4, new plot arcs and new goals are needed to be written by the author, so as to keep the rhythm of this light novel series.
I think the author makes the main character, Jinwoo, someone stubborn, choosy, controlling, self-centered, anti-social, etc. I hope in the future, Jinwoo becomes a little bit more tolerant, lenient, sociable, etc. so that he can be more "approachable" by the readers. Right now Jinwoo is like a and over powered (OP) cactus (as a person).