I think i might have mentioned it in this thread before, but genderbending isn't planned for this game at the moment. You will still have options on what happens to Romanos by the end of his content, but genderbending likely won't be among those options.
That is fair, but I'm thinking about some clichés when it comes to Dark Lords, on top of my fetish, that being the Four Heavenly Kings, or whatever, that serve directly under their Dark Lord in their conquest, with only the three women to become solely dedicated to the MC, that leaves one out for the Four Heavenly Kings cliché, unless Bogthos is going to be one of the Heavenly Kings, if so it will be a rather lop side congregation of direct subordinates, with three of them being corrupted women dedicated to the MC so hard that they will likely immediately call for the head of who ever so much as talks bad about the MC, and then there is Bogthos, I cannot help but feel super sus about him, I expect him to pull something in the end when you have amassed the forces of evil/darkness to its peak, only for him to betray you and take it all for himself.
Also it will hit the populous all the much harder when they come to realize that the Hero they looked up to, despite being a colossal piece of shit, for peace from the Dark Lord, now serving the new Dark Lord, possibly even still having whatever marked them as the Hero, though equally corrupted by the MC, rather than just being locked in a castle to be sexually tortured and drained of energy, where he could potentially be rescued in some form, or be killed off to have a new Hero be selected to take his place, because he would have no strength to oppose being assassinated because of the sexual torture and being drained of his energy regularly, over however long it would take to sneak into where he is being held. Besides, you can show that the party of the Hero has fallen and been corrupted, but so long as the Hero can rise up to oppose the Dark Lord, they will not truly lose hope of freedom from the Dark Lord's rule.
Also you made no mention on my comment of different races for the other girls. I get Misaki being turned into the Succubus Queen from what the MC was subtly altering her into being like, the others could develop into something completely different through the corruption because of who they are, of course they would be much stronger than normal, fitting of their role as a Heavenly King, being a powerful dominant variant of their species, like Misaki being the Queen of the Succubus.
From Yukako's religious standing I can think of three potential corrupted forms; A Fallen Angel, as she would hole heartedly worship the MC as her new God. Diving deep into the dark depths of the MC's corrupting power, and rising as a Eldritch Being, twisting logic to fallow her Dark Lord beyond the concept of reality. A Lamia, simply taken from "Monster Girl Quest" where one of the end game enemies is a Lamia Nun of the God the Protagonist is turning his blade to, as Lamias are depicted in their dedication to their belief and desires, coiling close to her lord, while singing the great redorict (can't figure the correct spelling for that, I don't think it is "redirect" as that is something completely different) of her wonderous Dark Lord to the masses.
Rina on the other hand being a proud and strong warrior could be corrupted into either; A powerful demon different from a Succubus, such as an Oni (yes, I'm a Weeb), using her colossal might to destroy anyone and anything that would challenge her lord. Being reforged into powerful beast that brings terror to all who would oppose her lord with hellfire and destruction, guarding all that her lord holds dominion over as an almighty Dragon.
Going back into my fetish of Gender Swap for a quick minute for the potential fourth member of the Heavenly Kings with Romanos, given his excessive ego I came up with two directly opposite, but fitting corrupted forms; A Slime, being the fodder race it would be the most humiliating for the now broken hero, but because of bathing directly under her Dark Lord's corrupting power she will become an overwhelmingly strong variant to serve her lord with all her heart and soul. A Vampire, known as the strongest and proudest of the Undead species (short of Liches that are powerful caster focused Undead), capable of dominating others to do her bidding in the name of her Dark Lord, all to drown taste his corrupting blood and of course seed.
