Guys I have theory! What if after sakuna killed his brothers he took in thier concubines just to provide and protect them.. like.. it makes more sense...cuz no. Of concubine is so much! ... And sakuna just read or take advice about s*x cuz he not wanna hurt his beloved...like.. it makes sense ?
Now I feel that grandma and that other dude was planning to take ahjin down ; hence she was telling him to run away so kang will suspect ahjin !! Ahhh everything is sh**!!