Origin Null - Part 1: How did this turn into an Eroge???

Overall Storyline Plan:
Part 1: Character Building
Part 2: World Building
Part 3-8: Extremely battle focused

Part 1 Synopsis:
Ren finds himself in the middle of a typical isekai reincarnation. He's given the typical mission of defeating the Demon King and saving humanity. What's not typical is the world he was reincarnated into. His mission is grand and important, even if typical for an isekai, so how come it's as if he's in an eroge? What's up with the women of this world? They're so forward that his modern day adolescent brain can't process what happening fast enough. His answer to this conundrum doesn't turn out like he thought it would. Join him on his journey to balance saving the world and balancing his women's wants and needs.

-Comments-
Ever see one of those stories where the protagonist clearly has a love interest, or multiple, but there is no relationship progress? Just the occasional feel good moment that gives the illusion of progress? Well, this story doesn't have that. Men are a dying gender, but are needed for reproduction. That's basic biology. There are even cases where they are kidnapped and confined to be used for...you know (details are not written - you just know that it happens). The protagonist isn't permitted to stay on the sidelines and do nothing even if he tried his best to.

Writing Style:
When reading Light Novels, I sometimes get confused if it's not made clear who's talking when there are multiple characters. I can read one line and see how two different characters could say it, with the underlying meaning being different. I decided to make it 100% clear who's talking. The easiest way to do that was to make it similar to a a script. I also imagine it as an anime in my head, which influenced the writing.

My writing style for using quotation marks is an amalgamation of the British and American styles (which I found out not too long ago and have never been corrected on). I think this style incorporates the good of both and makes sense. My apologies if you're not used to it, but I hope you aren't terribly bothered by it.

Important Notes:
-this story isn't the most lighthearted, dealing with topics like depression and forms of heartbreaking abuse for certain characters.

-tough choices have to be made, not everything can have a happy outcome, but the MC will try his best.

-imagine you were suddenly sent to another country and know nothing. Being isekai'd isn't as easy as stories make it out to be. Not everyone can miraculously adapt right from the get-go, and they may never adapt.
From culture to food, society and social norms. Everything is different.

-the age of adults in this story is 15. This is due to a range of factors and is ultimately important for the overall story, so it can't be changed.

-there is some nudity, but it's not 'ecchi' per say. Adult things happen frequently, you can tell that they have happened or will happen. I can't emphasise enough how important intercourse is to this world, for more than just basic biology or for fun times. You will read into the reasons at some point.

-this is a war stricken world, so unsavory things happen, even to those below adult age. You hear of these things but don't see them directly. As I was writing, the way I set up the world naturally brought these things to light. It's important for world building and character creation/development. I'd rater not conveniently avoid these topis, but I try to keep it as light as I can while considering the circumstances.

-I am a fulltime worker who writes irregularly and slowly (physical typing speed), as well as often mulling over one sentence for several minutes. Progress will be slow once posting catches up to what I'm currently writing.

-This is a long series and is a multiverse. To elaborate; this main storyline is currently planned to have about 8 parts. Part 1 is projected to have 3-4 books.

-the picture is AI generated and not an accurate reflection of the character.