RAW:
Part 1: /g/812737/038cc6f010/
Part 2: /g/891934/8082b614c1/
Part 3: /g/934939/104748b9cc/
Part 4: /g/1021649/1cb9510677/

English Translated:
Part 1: (Poor Grammar) /g/814075/b349608117/
Part 2: /g/939863/20afdd644e/
Part 3: /g/940649/2b2ed0b577/
Part 4: untranslated

Base +30, FabulousCupcake +26, Not A Masochist +6, mayama12811 +8, Slobber +27, chcommunity +15, Ooe Kintarou +10, asde22 +6, Daddyfatsack +6

Thanks to his KC doujins, mind kinda established that page 8 expression as 'Zuihou face'

Base +6

this man is a shitty pussy

Base +3, iamthegang +8, irisation21 +8, Dicraw +6, Ooe Kintarou +10, pond39267 +6, th3divineone +6, Almanik -11, Xerxis -8, cronur +6

There's nothing wrong with snapping and going full Asanagi, onii-chan. Your psychotic sister and cuck of a girlfriend need some authority.

Base +4, cronur -6, Azure_Shockwave +6, iamthegang +8

居然画了追加剧情

Base +5, sd5745124 +8, hondawhr +24

Can someone write a brief summary of what happened in this chapter? My kanji knowledge is still very little

Base +4, kmochs -6, HitmanPAC +6, cronur +6

The onii-chan shouldve manned up and made it into a threesome and impregnated them both, but i forget this is reverse ntr so he's bound to have been stolen and his girlfriend turning into a cuck. Still rare though as there are barely any reverse ntr stories, but too bad this one didnt dive into the gf's point of view for longer content.

Although I still found this chapter to be too short, so when exactly did the gf found out and was mind broken into accepting it? Was it ever since the first chapter as somewhat hinted here? I couldve sworn she started her suspicions during her bfs birthday where she had that 'dream'.

Base +6, chcommunity +15, knucklesluigi +6, Soyungundam -6, Ooe Kintarou +10, pond39267 +6, Almanik -11, cronur +6, Fighnjaci +11, Daddyfatsack +6, nowittycomment +12

feel bad, rua

Base +6

@Barcia, @ShikiN7
This chapter was drawn after chapter 3 and long before chapter 4 came out. It was uploaded very recently only because it was not sold in comic market but during one of a smaller event and therefore the prints are very limited.

WIsh this background, you should now know that the GF became suspicious after chapter 3. The dream she was referring to in this chapter was when she was fed sleeping pills and sleep by the brother-sister-having-sex-all-night in chapter 3.

Base +6, cronur +6

Thank god this got uploaded.

Base +5

oni chan the ultimate cock

Base +12, cronur +6

@ShikiN7
Well, the guy isn't entirely at fault. The gf was a bit too dense to the fact that she wasn't satisfying the guy, which led to him being not able to completely push the imouto.
Still pretty hot though, double immorality. Looking forward to the author's next work/series.

Also a bit delayed, thank you for uploading this uploader

Base +7