I enjoyed the premise of the ML using his knowledge to improve the lives of his people and helping protect the witches. It's got really nice moral aspects which I appreciate. ML isn't a huge pe*vert or anything which is good, it keeps the romance pretty low-key. It's not a ridiculous harem, just Anna and Nightingale. It's very much a story based on plot and not character development which is important to keep in mind when it comes to the characters and their shortcomings.

The best part for me was the witches and Roland/ML's interactions with them in the early-middle part of the story. Later on, after the war against the Church, things start to drag quite a bit and I think it got away from what made the story fun and enjoyable to read which was Roland's interactions with people and the slice-of-life elements. It leaned a bit too hard into the demons/God/Dream world timeline and I feel like those parts were never quite as enjoyable as the early-middle parts. The ending was quite confusing and, to be honest, if you told me this was how the story would've ended when I was first reading it I would've been so confused.

The way the ML infuses the science and magic together to get a way to upgrade witches' skills also good.

Roland's first 3 technology advancements are actually cement, firearms and steam engine which actually makes a fair amount of sense. The cement for building his wall and housing is often overlooked in the types of stories, and the steam engine essentially drives industrialization and allows him to mine more efficiently as well as to machine more parts for things he wants to construct (like boring gun/cannon barrels). The firearms are actually fairly limited in the beginning because he can't mass produce them, and his saltpeter supply is limited. Saltpeter is already used in the world as a food cooling agent (kind of like the Romans in RL). Not sure where he obtains the sulfur from -presumably it's mined like like iron. He actually moves on to import saltpeter later through the merchants until they're cut off, and then he starts producing his own saltpeter farm (using the manure/u**ne extraction method I believe).

It's interesting to see that while he has some basic knowledge in other science fields like chemistry he's far from all capable, and end up recruiting alchemists in the world, teaching them basic chemistry and having them research developments like creating a primer/explosive and ethanol. These endeavors often take month to pan out even with the assistance of the witches. You can also see examples of his lack of knowledge in metallurgy where he ends up having the witches experiment with different alloys and record their properties (one of them smelts the metals together, the other one breaks them down to their individual components). There's some level of detail here but probably nothing beyond high school or freshman college level type of references. While I can't follow it 100% I vaguely understand the concepts, and appreciate the effort as opposed to some hand waving like "he mixed random chemicals together and voila! explosive primers".

In terms of production shortcuts the 3 primary witches are Anna for her smelting and material cutting, Lucia for breaking down material to constituent parts and Soraya for making plastic/polymer coatings. Over time they contribute greatly to the advancement and production of Greycastle. Healthcare is handled by Nana for injuries and Lily for anti-bacteria/viral applications. Agriculture by leaf via her plant hybridization along with irrigation and fertilizer advances. Overall it feels like the witches are enablers of technological development as opposed to them snapping their fingers and just making things happen.

Overall in terms of world building I felt that the pace and progression were quite reasonable. After surviving the first winter with his walls and guns he moves on enrich the lives of the citizens of border town by improving their food and housing, implements an education system to raise worker skills to drive his industrialization efforts, starts a propaganda campaign to shift public sentiment, overhauls the economic situation (widespread employment, fixed grain prices, luxury goods for those employed people with disposable income) and fights off an invasion.

It sort of builds up in scale from there until he's king of the continent where upon he realizes the literal world threatening demons, and the secrets of the Church whose original purpose was to fight the demons but has since become rather corrupt even though it adheres to the original purpose. This part features some interesting magic vs magic confrontations as well as tech vs magic confrontations. There was a time travel/cross world holy grail of sorts that was nice to see (i.e. what's one of the most destructive weapons known to modern man created "simply" by smashing together some special isotopes at high speeds to reach critical mass?).

The Dream World component is a little mixed for me. It was nice that the Taquila witches were able to experience modern day life in a reverse mirror scenario, and the KFC scene was great. The acquisition of martial powers by Roland however felt very odd as although it was cool, it just didn't fit his character personality and it seemed the author realized this and abandoned that plan. Originally I was expecting a Matrix Reloaded moment when Roland realized he had powers in the real world but that didn't happen. I'm disappointed but also relieved that it didn't happen.

The ending was rather deus ex machina, and while there was a prologue of sorts, I really wished it covered more of the characters that appeared in the series as I wondered about how the other witches were doing. It just felt really rushed. It would be nice to see a gaiden/side stories featuring the other characters.

There seems to be a number of people who believe that a mechanical engineer would be unable to design a simple gun, steam engine, plumbing or have basic knowledge of related science fields like chemistry, material science, etc. Similarly people make the claim that the author is "pretentious" to show off his knowledge of various details of chemical reactions, knowledge of the periodic table, mathematics, etc. that Roland couldn't possibly have as a "normal" person.

To quote her Holiness: "Anata Obaka?"

First of all I'm not a mechanical engineer, and I was not educated in the China. I do personally know people with what's equivalent to a electrical engineering degree from China very well though. Science and engineering has been highly respected and sought after in the last 40 or so years in China, and traditional education in China is super rigorous with lots of memorization. It's completely believable for people to be able to remember advanced math, the majority of elements in the periodic table and be able to understand the mechanism behind common mechanical devices even decades after being exposed to them in school.

I would imagine as mechanical engineer, that making a basic flintlock muzzle loader is trivial. In fact I would imagine a high school student with some interest in science can create one or at least a matchlock fairly easily given the materials. It's just a metal tube plugged on one end, stuffed with black powder, wadding and a lead ball with a touch hole to ignite it. I say this as a firearm owner -although I don't have any black powder weapons or muzzle loaders because they are very smoky and bothersome to operate. I've never actually made black powder before (mostly because I can't find a cheap/easy source of sulfur -saltpeter is fairly cheap/easily obtained) but I have made rocket candy before. Hmm... seems Amazon sells sulfur fairly cheaply but in 10lb bags...

Basic steam engines are actually fairly simple in design. Anyone who's looked at a How Stuff Works book as a child or teen could probably figure out the operation. It's a little more advanced than a hand pump in design but as a mechanical engineer you would probably need to understand some common devices like a steam engine, a combustion engine, electrical motor, etc. because they are so well known. (I was tempted to buy a Sterling engine a while back but I resisted.)

So basically this is not some super specialized knowledge. It would be entirely expected for someone mechanically inclined to be able to create such devices with a human smelter/CNC router (a.k.a Anna). To suggest otherwise is rather silly.

On the topic of "Guns are bad"... In a world where demonic mutated creatures routinely kill people, and neighboring cities send their soldiers after you... guns don't seem very bad... in fact they seem great. Plus note that Roland doesn't actually sell guns to random people. Some of you might ask "What about accidental gun death?" to which I reply: most of the weapons Roland creates are (presumably hammer fired) revolvers, bolt action rifles or (presumably hand cranked) machineguns. You'd really have to go out of your way to accidentally shoot yourself or others after some basic training. To put it another way: you are probably just as likely to fall on your sword and stab yourself.

On the topic of "The Church is always evil"... Well, when any organization brainwashes you not to think critically, and just believe they're the good guys and everyone against them is evil... I suppose the other common group that fall into that category are facists.

On the topic of "The witches are cheats"... That's sort of like reading a superhero novel and shouting "I can't believe there are people with extraordinary powers that normal people don't possess! What kind of story is this!?" Having said that, the witches' powers are useful but in general but are not game changers without a fair amount of work on Roland's part. There's usually a fair amount of experimentation, exploration and prep work to bring out their real effectiveness.

On the topic of "There's no diplomacy"... Most of the leaders of other nations he encounters are already quite hostile to him in a "there can be only one" way, and Roland is not a politician by any measure. In fact many people feel that he's not a very good king by the common definition as he doesn't monopolize power. He is however a decent leader, and eventually ends up cooperating with two major forces that were very hostile to him.

On the topic of "There's no relationship progress or why was the harem suddenly dropped?"... He's a workaholic that died in his previous life. In this one he's initially in a Sword of Damocles situation where he's liable to get killed if he doesn't develop fast enough, and later it's a race to save the world. He's kind of busy trying to you know... survive. As for why his "relationship" with Lightning didn't progress, the answer is there was no relationship. She's a young girl who sees him as a father figure of sorts -not a romantic partner. As for Nightingale, that's obviously a spoiler.