BlossomWolf's manga / #Adorable(77)

I don't know who did the historical research for this story, but a royal eunuch wasn't castrated so they would be "efficient servants," or whatever. They were castrated to prevent them from having sex and impregnating the royal concubines/consorts/empress and messing up the bloodlines. In other words, to make sure that the king/emperor's children were really his kids and not someone else.