So, I have been read the JP novel, A Demon Lord’s Tale: Dungeons, Monster Girls, and Heartwarming Bliss. It's a great novel as far as isekai novels with a slice of life tag can go. But, this particular novel has a weird problem. That is, the male protagonist (or the author) avoids the topic of sex or mating in this case like a plague. The protagonist Yuki is unlike other beta JP protagonists we see in most novels, where they are too afraid to take the crucial step in their relationship and marry their harem members. Yuki did not wait for long and quickly married his harem members. But the problem starts from here, that is he entered a perpetual state of "Sage Mode". So far in the novel Yuki seems devoid of any carnal desire. He feels both attraction and love towards his wives, but so far he didn't show any feelings of lust for them. He doesn't have the male instinct of reproduction. Even when he is in the bath, alone with his beautiful naked wives; Yuki only has the feeling of attraction and love, no lust is present. It's the same for the female characters also. Some might say that Yuki is too innocent and pure, but we should remember that before his reincarnation he was an adult. He cannot be that much pure. In the end, there can be two possibilities: Firstly, Yuki lacks a male reproductive organ. Secondly, the author himself is purposefully avoiding the topic for some reason. Maybe he has some sort of past trauma about the particular subject? Most likely we will never know, but Yuki is certainly the Beta Demon King adept in the art of the Sage Mode.
That is another 'trait' of lots of isekai, harem and slice of life novels, and why readers of other types novels like CN and KR prefer them over JP novels, it is like a template of some sort, if slice of life, harem and isekai are present then there is no further 'romantical' development otherwise authors might as well add NTR, cheating and rape into the JP novel, of course there might be exceptions but the norm would stop at what you described as 'Sage mode'
It's kind of a huge disappointment. Giving the some Dragon Lord babies would have made the story so much better.
Let review some of his Harem member, shall we ? 1, Lefi the Dragon: Describe as a teen(?) girl, in any case, she looks underage and ofc as an Adult, Yuki (who i hope is NOT a lolicon) cant have the mentality to touch her yet. He only < 1 years old in this world so the common senses of the Old World still affect him. He gonna need some more time to change his mentaility to be able to feel lust for her 2, Nell the Hero girl: If the manga is to go by, Nell looks more mature than Lefi. But Yuki only saw her as a friend as first and still kinda iffy about marrying her, so he cant really take any more step ahead than what he can do now. 3,Lyuu the Warwolf: Same deal with Nell, at least he had the common decency to not 'molest' her when they are still Master-Servant, only to touched her ears and tail AFTER they are engaged. Their marriage is still not official, still on the 'fiance' level according to her dad. So cant really f*ck her while her dad is out their watching over them 4, Illuna the Vampire: she's his sister for Christ sake, cant really do that now can you ? 5, Enne the Sword(?): she's his daughter for Christ sake, etc... 6, Shii the Slime and The Three Ghost Girls: Loli, Underage ---> FBI still exist inter-worldly Again, Yuki is <1 years old into a new world. Yes he was reincarnated as an Adult, but come on Dude, tell me if you got new awesome power to play with and basically a dungeon worth of Sandbox to mess around with, wont you gonna start building shit while giggling like a 10 years old while doing that. Give him a few arc to develop a real Adult Mentality and before you know he gonna f*ck them all
I kind of understand. But the author could do better by giving a clear reason for his perpetual sage mode, so that it can make the story flow better.
I think the doubt is whether actual adult development and mentality can actually happen?. considering the trend, i doubt it. could be wrong, which would be a nice surprise, but i doubt it from experience
For a country with a gigantic porn industry, I have no idea why these authors don't have the balls to make their fictional characters bang their harems. I mean the boy likes girl, girl likes boy, girl wants the D, but the boy says no. That just doesn't make any sense.
Well, I'm sure that every Japanese kid is very well acquainted with the matter, but it's the adults that are having problems with the subject, considering the recent low birth rates in Japan...