Cruel, huh? In that case:
IF YOU'RE OKAY WITH VNS:
Kangoku Senkan/ Any game from Anime Lillith- Rance H20 recently uploaded the whole collection and in general, games from Anime Lillith are all about turning whatever the females are in the game (humans, elves or otherwise) into living cum-dumps with a focus on brainwashing. As the main character, you get to see most of that in action, so you don't get cucked in this game at all.
After Service Gangbang Addicts- The story is that you move to a new school where your little sister is, but it turns out that a couple of girls have created a "Gangbang Club" where your sister is basically the sole toy of the club. However, there is also a save where everything is unlocked, including a mode where you can fuck the girl who caused all of it in the first place, both as a girlfriend where you forgive her, and as revenge for what she put you through.
Otaku Fantasy- Basically you play as some random guy who's only redeemable quality is his dick, and the games mainly focus on taking stuck-up chick and turning them into your personal sluts.
Bunny Black- Although I haven't completely finished the game yet, the main story is that you're an adventurer who tries to fight against the Demon Queen, but dies and is resurrected as that queen's minion. THIS GAME, HOWEVER, IS PRETTY GRIND-HEAVY, SO TAKE THAT INTO CONSIDERATION. Also, some of the "cruel" sex becomes sweeter later, so this may be a miss for you.
Miel/Norn Games- Pretty much the same as the Otaku Fantasy games or the Anime Lillith games where it's all about brining stuck up bitches down the ladder. There's a couple too, so whatever suits your taste, although the translations can be a little wonky.
IF YOU DON'T LIKE VNS:
Harem(Ren'Py)- There are options in red where you can take whatever woman is front of you with some method requiring cruelty, deception or some other for of trickery. (This game is still in development, but is pretty far in. so there's some content for you to enjoy)
Harem Collector(Ren'Py)- This game is usually pretty light-hearted overall with lots of tongue-and-cheek references, with sprinkles of cruelty here and there. Otherwise, who knows if this is what you're looking for (Like Harem: still in development, but lots of progress and content made)
Waifu Academy(Ren'Py)- There are some cruel bits here and there, but most of the time it becomes sweeter later. Otherwise, has a dark story with a light-hearted environment at first. (Still in development, but there's a decent amount of content there. Not as much as either Harem or Harem Collector, though)
Don't know if all of these games are what you're looking for, but I tried to scroll through my games' folders for any game with some degree of cruelty.
