It's just Larian being Larian, as soon as they showed the cutscene of him chilling without a shirt on, I just skipped straight to the "i want to sleep" line, and cut it very short. They just have to make things weird.
The Mind Flayer who retained the identity of a human is also a human, and deserves the right to love. He is very lonely and can maintain his Dream Guardian form during sex.
He's a mindflayer. Wither's himself tells you Illithids do not have souls. Mystra also chimes in on this during one particular ending.
He's also a pos, willing to do whatever to whomever to advance his agenda.
So? Some of us really enjoy a dark romance bad guy plot. There are many other bad guy romance plot options, this is just another of them.
I was mainly just touching on the fact that he's not human, or who he was before ceremorphosis.
I do think expanding on the Empreror's romance would be a poor use of resources. Development of anything that the mass majority of end users likely will never interact with seems misguided to me. Additionally, it only adds another layer on the 15 different plot roles The Empreror is trying to fulfill and another one that doesn't really make sense when considering most lore. Daisy - a manifestation of your ideal guardian (that we customize at the start of the game) seducing you as manipulation sure - A genuine romance with a dark triad chad mindflayer though just isn't really a thing with Illithids.
