There is no real arc for them so far.
In Volume 12 of the lightnovel they have more interaction with each other and all looks quite polite inbetween them. It seemed that there might be more going on following a thought of Lahan that he admires her beauty but we did not get any more than that and with Vol 13 out it also seems that this will not be the pairing it gets to.
Or maybe I read too much into it and it stays with this.
Volume 14 is up on j-novels for weekly reading!!
Spoiler
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According to the novel, these are the following characters that has romance in the story:
*Jinshi and Maomao (Jinshi doesn't want Maomao to steal her freedom. There was a point in the novel that they should sleep together and Maomao knows the consequences of it that the moment they made love, she will no longer be able to leave the inner palace like what happened to Lady Ah-fou when she slept with the Emperor. Jinshi love Maomao but she dismissed him that night because he placed importance in Maomao's freedom. The emperor and other officials are pushing Jinshi to take a consort)
*Lihaku and Pairin
*Basen and Consort Lishu (Lishu will no longer be the emperor's consort later on. She is like the daughter to the Emperor and Lady Ah-duo)
* Lahan and Yao (Yao is Maomao's friend who came from a noble family and they both working in medical clinic inside the palace later on in the story)
*Kan Junjie (Lahan's older brother) and En-en (she is also Maomao's friend and co-worker)
*Baryou (Basen's older brother) and Chue (spy of the imperial family). I really love Chue in the story.