He dies together with a female store clerk and they both transmigrate. They reunite after he is accidentally teleported to another kingdom at age 6. He saves her life, family and village. They reunite happily as friends in foreign lands, then spend a month dungeon diving to deal with a dungeon overflow. That's all well and good, but then when he leaves to return to his home (in another kingdom that is at war with her kingdom) she decides to go with him.

I don't buy that even a month of risking their lives together would make her want to abandon the home and parents she has lived with for 6 years for a guy she's only known for one month (they met for the first time the day they died). I don't buy that her parents would support her decision. The author completely failed to sell this plot line to me. If you (the author) really want them together, have her attend a school in his kingdom once they're adults and the kingdoms aren't at war. Who the f*ck entrusts their 6 year old daughter to a 6 year old kid (I don't care how f*cking strong he is) ?

the reason why the other transmigrated girl is entrusted to the main character isn't because she trust or that her family trusts him or anything like that. It's because she is becoming a well known holy magic user in her town which in this world is enough of a reason to be kidnapped and ens*aved. They bring up multiple times that both the MC and the other reincarnated girl have to keep their holy magic a secret otherwise both nobility or A-rank parties will try to snatch them up. So the Count of the area decided it would be best for Clarisse (transmigrated girl) to be sent off else where to get stronger before anything else.

At first he wanted to only protect this japanese girl from his world (they are of the same age 20 years and were born again at the same time. All fine in my book. But he gets a harem... a big one... with a lot of disgustingly h**ny children..

Second is thefact about him hiding all traces of his japanese origin to avoid the mu*derer from his world... Yes at the end of vol. 4 the author just decided to name their ridicoulously prominent party Reimei. A japanese word that ONLY these three know... so yeah.. At this point the story willl probably go down the drain.

The MC managed to defeat hundreds of goblins everyday but now he's struggling against one hundred with whole lot of adventurers and knights helping? His mp should be enough to slay thousands of normal goblins all the way to generals and it's not like he can't fight with his sword, I've even take him doing healing into consideration but just can't imagine how the heck the town got so bad with just hundreds of goblin, geez.... if the goblins attack a town in hordes.... they'd be just practice target to archers if they not come in thousands of hordes... at least that's the impression I got after reading. The story didn't mention any archers at all when yhe attack happen was the most unconvincing

In an earlier arc, the fiancée of MC's brother lost her arm and MC managed to reattach her arm and heal her. Then a lot later MC says that the girl doesn't know that he can use holy magic. Yeah, he just performed a miracle-level healing on her...

Another one like this there's a school holiday so MC and his buddies have time to visit home. Everyone tells them to avoid a certain city because it's dangerous, MC agrees that they should definitely avoid going there, and then when they discuss possible routes, they choose to go through that city without even mentioning the risks they talked about earlier as if that conversation where they agreed not to go there never happened.