
so who's this guy? im confused with the portrait is he like an evil twin or what ヽ(`Д´)ノ

Nope, the dude took the official royal family portrait, made a copy and painted himself in replacing the emperor. He kept the kids and the wife and everything. He even changed the color if the boys' hair to match his. And now he just sits there and looks at it. I've seen a lot of unhinged obsessed villains in manhwa before, but that's just a new level of creep dedication.

According to MC, he spent his whole life resenting/being jealous of the Emperor, so I'd assume it stems from his inferiority complex rather than only being bc of the Empress.
At least that's what I'd hope, it would be great to get something a bit more complicated than "he married the woman I was interested in".

i kept pushing through the last 50 cp bc the start was good but the harem is ridiculous at this point and the new characters (females) keep getting more brainless as the story goes .... dropped

Davey is only interested in the demon lord that he is with. He's not interested in anyone and doesn't entertain anyone except the demon with him. For me, it's worth reading as it tackles improvement of politics and family drama lol, but if your not okay with it, then go. Hope you find another manhwa you'll enjoy
welp thsi 3 chp felt so short