It's kind of both ways. It's battle sex so you take turns doing sexual stuff to each other, whoever makes the other cum first "loses" the battle. If you lose, the girls keep using you until you're drained dry. If you win, I mean, you just fucked them into orgasm so I guess you just win.
The broader theme however is that the 'heroes' cheated the system by becoming succubi, which prevents them from being physically hurt, only sexually subdued, and they used sex to catch the dark lord (you) by surprise and overthrow him. He then says screw it, whips out his dick, and charges back in full erection.
There are elements of femdom, especially with the way the girls talk to you, but it's not like Monster Girl Quest where almost every sex scene involves dominant girls preying on a submissive Luka,, 99% of which are loss states or pseudo/reluctantly consensual.
The dark lord has no problem dicking down the girls and is pretty dominant about it. I wouldn't put the tag if it were me, but the site's tag system is already vaguely useful at the best of times. There are a ton of game with clear tags that don't have them, or games that have 1/10th of an instance of it as an optional, easy to miss joke and it's the first tag there.