Zac is camping with some friends when Earth gets inducted by the Multiverse System. Since Earth doesn't meet the Multiverse standard, it is fused with three other worlds to create one larger planet composed of random pieces of terrain from all four worlds to create a D-grade world. This is theoretically a great opportunity for potential Cultivators, since most worlds are inducted as F-grade. The first thing that happens is that one third of the populations are deemed potential Cultivators, i.e. they can naturally absorb enough cosmic energy to efficiently improve themselves, and are teleported to Tutorial Villages. Sadly for Zac, he's in the other 66%. All he got was the message about the induction and then a message that he's in the exact spot where something else is supposed to materialize and the System can't merge them. Since two beings can't occupy the same spot they have to roll for it, with Zac rolling 1-100 and the "Herald" rolling 1-100,000 because of its level. Who said the Apocalypse would be fair?
Obviously, luck was on Zac's side, but he's still alone in the woods and there are giant demon dog things roaming around. On the plus side, he has a small hatchet meant for chopping firewood so he technically has a weapon. He also has a seemingly impossible quest to kill the other Heralds and General of an Incursion force (turns out a newly inducted world is a money making opportunity for people in the Multiverse). Since he didn't get the advantage of the tutorial, he's learning by trial and error relying on what he knows from gaming. Dungeons and Dragons and its descendants got a lot of things wrong, and so does Zac, but he perseveres. He finally gains some contact with the world off his island, but humanity is busy exploring every dystopian trope and doing little to fight the Incursions. There are two other known races. The Ishiat are a beastkin people and possibly faring even worse than humans. This is because they are mostly agrarian, except for one steampunk style faction, and the System eliminates most tech weapons. On the other hand, the Zhix are an insectoid theocracy with legends of evil beings, ostensibly Cultivators of some kind, who tried to rule their world, so they refuse to use the Cosmic Energy necessary to level.
I'm mostly familiar with System style litRPG books and not that many of them so the Cultivation aspect of this series is all new to me. While killing is the fastest way to level there are limits to their progression unless they also gain knowledge of the Dao. For instance, Zac's skill Axe Mastery helps him unlock the Dao, or concept, of Heaviness. His first epiphany involves the physical weight of something but his second is about the weight of emotions like grief. Heaviness is a common Dao but everyone understands it in unique ways. I also haven't seen another book in the genre that concerns itself with the idea of base building. Zac starts with a small camper in the woods as his "outpost" and he can buy improvements such as defenses and shops as he meets requirements. He is essentially building a town from scratch. Now if only he had people to live in it.
As with most of these stories, Zac begins with serious advantages. The roll to live versus the Herald, a level 30 creature, came with great rewards since he got credit for a solo kill, and taking on the Incursion promises even greater benefits. Of course, others in the new world have similar advantages from the Tutorial, so he's not exactly "overpowered" in the traditional sense. The general plot lines about surviving in this new harsh world and searching for his lost family aren't new, but the Incursion story line takes some unexpected turns. There's not a lot of depth to the writing in this first book, but that's common among web-serials that gain enough popularity to get published as e-books. Overall, the scenario, classes, and various races are all interesting and I'm moving on to book two. Defiance of the Fall is up to 14 books so far with excellent reviews and I do see that many say the writing improves as the series continues.