I just realized...at first I thought the team name Siarah was a typo of Sarah, but what if it's a combination of Sia and Sarah? :0
Since Sarah keeps referring to someone.
I'm two year late, but I just really want to say, it clearly states that it's according to the PRC, it was banned in 1997, which is much more recent than those time of dynasties where they had concubines.
I let the chapters pile up before binging, and when I read this chapter I was so excited to comment that the Yan in his name is also my chinese name! Share the same first name XD. 424 chapters for this discovery haha.