Def not Asia or Akeno that would be a bit too much harem sniping. Idk about Koneko, i mean she is one of the better girls (flat is justice) but that would also lean into harem sniping which is one of the greatest betrayals among bros. Sona is A-OK though because Saji is a fucking simp.

This is actually way better than I was expecting for something that came off to me as a joke (this statement is light-hearted banter so please don't kill me). It would be pretty funny if he does end up a 'One-Punch Man' kinda character... just not overly OP... just very strongish. And maybe Matsuda ending up a 'Genos' kind of sidekick route? Nice solid start though.

I think you should keep the girls from the Occult club out of the Harem.
A. because they are overused in all the harems.
B. Because they aren't even that interesting
C. Motohoma should keep his knoledge of the supernatural a secret for as long as he can. pnly getting discovered by Sona after he starts training magic and she notices that he has mana/magic energy/mp/whatever you want to call it in his body.

I also believe that you should keep Motohoma a human and not turn him into a devil. atleast until he's dying because of a stray devil or something and Serafell Revives him so Sona won't be sad. I chose Serafell because she doesn't have a peerage. So you wont need to write more character as I've noticed you aren't very good at that.

I believe you should stay out of the Raynare fight and come a day later to search for any Holy Church weapons from any Exorcist corpse they forgot to erase.

I don't have any problem with the Sona route you think of writing. I have'nt seen anybody actually do something with the chess win against Sona. We are told that She will only marry somebody if he/she wins against her in Chess. alot of authors do the chess game, win at it, and then do nothing about the whole getting married thing, so that could also be a way for him to become a Devil if you dont like the dying part.
Have him transformed during the wedding by Serafell. as a Maou should have the political power to be allowed to do that.

About some japanese stuff, I myself am not japanese but we have a club at my school where we learn the culture with a teacher who lived there for ten or twenty years. so here are the things you should remember (this purely optional, I am not forcing you to use these)
1. In Japanese families the wife doesn't go to work far. She stays at home as either a housewife or works somewhere in the neighbourhood(a convinience store clerk or a kindergarten) while the husband does the "money making work" at the office or factory.

2. In a standard japanese breakfast the woman has to wake up earlier than the man and make the food before he wakes up. The most standard breakfast is Rice, Fish and Miso soup.

3. in japanese trains people will sometimes fall asleep and use your shoulder as a pillow. This is because A. they dont have a pillow on them or B. They are trying to make you uncomfortable so you will move and they will have more space.

On the subject of Magic. In DxD Human magic uses formulas like magic circles and runes (FlameShape{ball}Projectvelocity{80A Fireball shooting at 80 KPH) meaning that Motohama would need to be good at math and programming.

And Japan uses the metric system so use kilometers insteam of miles and so on.

Good luck. My PM system does'nt work so if you need any help ask me in the author notes on your next chapter.

P. SAre you going to do "Naruto say shit part 3: Sasuke says fuck" anytime soon?

At last a good motohama dxd insert, keep it up can't wait for the next chapter.

So considering his past as a marine, perhaps his gear could allow him to summon a group of marines?

I prefer almost all girls in dxd, except Issei's harem members. Your choices, author-sensei

Great chapter

and chapter 5

maybe he discovers he has an information gathering sacred gear. since the past version of him only cared about sex-related things, he probably tried and tried to see a girl’s measurements and eventually was able to use the sacred gear for it, but had no motivation to try it with anything else and wasn’t in good enough shape to fully unlock the gear anyway.

Will he fake not knowing about the contract's existence?

Seriously, Akeno, why would you, inadvertently choose her?

I believe she was, called a B.D.S.M type character was she not?

Ahem, why, ANY peerage girl, just why?

The peerage girl's, are more-or-less, safe-zone girl's, didn't you know that?

Honestly, the one common theme, is any peerage girl, is suitable, because,
their the closest to the story.

Thanks for chapter.
How about actually trying to save raynare and her group from dying. With than in mind, you can get Raynare, Mittelt and kalawarner in the harem.

If he isnt one punching everything in 2 years I am going to be very mad.

please put Asia in harem. hate as iseei's relationship. Koneko depends on how you build your relationship with Motohama.
I'd like you to join the harem. Tsubaki Shinra, Reya Kusaka, reynare

Well that a relief you can’t quit on us