Is there any hint of mpreg?

Probably not. Early on in the story when they were just getting married, a servant or someone told Doram that he doesn't need to worry about kids, since when the prince wants an heir he can easily take a noble concubine and get her pregnant, so Doral is just his life companion

I havent continue yet, then will there really concubine to the prince?

Not sure the author didn't say anything

My delulu ass keeps searching buddy... Sometimes mpreg is a surprise reveal towards the end in these stories

I pray for ur wish to come true

thank u kind stranger