I just saw someone drop a link to the Thai trans of chapter 8 and 9. Here:
https://liqueurstranslate.blogspot.com/2020/08/isekai-de-seidorei-to-shite-ikite-iku.html?m=1
Check it out to see what happens next and also for the brother reveal lol
omg yesss thank you for the confirmation! I've been wondering abt this in the way back since lucian was said to be his brother! because Lucian have the family picture w black haired brother too, but then in shu's flashback, he have a black haired sibling. it was clashing to what every one is saying.. i was like "but it was just a few months of separation, like how can his brother be bigger than him?" but then everyone keep saying this and that so i was convinced because we all dont know how it'll turn out
now it all make sense!!! this really remind me of my comment and theory way back, thanks for the spoiler too!

lmaooo and here we all thought lucian is the brother but SIKEEEEEEE