Fiction from previous decades or centuries, written by and for women, may have got some tropes today aren't too popular. Now people from this generations want to do the things with other style, but this doesn't mean we have to reject all the past. And most of villainess/female antagonists from female/shojo literature aren't the villains/big bad guys from shone/male fiction, because female writters and reader have got different tastes and points of view.
Some "good" villains have got some pieces of "anti-villains". Usually the dark lords have some some tragic background, but in my opinion the true tragedy is the end of their curses are nearer they can imagine, almost front of the own noses, but they are too selfish and proud to try the redemption and leaving the dark side of the force. Really they are dooming themself because they are rejecting the teaching of the piaous souls. They are like drug-addicts who don't want to reject their vices. And their sins are worse when one of them comes back to the good path, and with her sacrifice shows the right way. It is tragicomic as when in the end of the story the main characters discover (too late?) the antidote against the ghoul bite was those flowers from the covent what they could watch everytime, or the waters from the source of a sacred place.
A character as Daenerys Targaryen, the khaleesi, the mother of dragons, may be an interesting (female) darklord.
If you want dark lords the web Fraternity of Shadows has got enough to feel sick. Literally more of hundreds, and I guess it doesn't matter about them to be canon or not. In my land we say "
don't see teeth of gifted horse" ( = if it's free, a gift, then don't worry about to be enough good because that is better than nothing).
* Ravenloft is gothic horror mainly, but with some space for the dark comedy.
* When I want to add a lot of things the demiplane becomes a too small "sandbox". If I want plots about conflicts between supernatural factions, as vampire clans and werewolves tribes, then I need more space, maybe not only a complete planet, but a "crystal sphere".