I am the Architect of your Torment! -- Did I go too far (like in terms of decency/vulgarity) with this villain?

So, big wig megacorp CEO makes a deal with the military to create cyborg assassins. Children are kidnapped and experimented upon until they find the perfect test subject. The CEO is sort of like Emperor Palpatine in STAR WARS where he's in the background, pulling the strings and doesn't meet the big hero until the very end of the story.

The CEO (a 30 something Bruce Wayne type; handsome and built like a brick shithouse) turns a blind eye to all the awful things the children are put through including all kinds of physical & mental abuse, The Dragon (A merc leader and the CEO's love interest) is given full freedom to heap whatever kind of "training" she deems necessary on the kids and the protagonist.

My protagonist is an amnesiac and discovers a part of her backstory where she grew up in a brothel and was once forced to perform sexual acts for a very special client who was paying top dollar for someone underage. The memory of the event sort of causes a BSOD for her and even mentioning it is a berserk button.

At the end of the story, the Protagonist and CEO finally meet where the latter is in prison. The CEO openly mocks the hero and says that she's stupid & naive to think she has friends and allies when in fact everyone is using her for their own purposes. He calls her "a whore, in more ways than one" (he knows she lived in a Brothel thanks to The Dragon. The Dragon herself used to insult the hero like that) and mocks her questions on the how's and why's she was victimized. His reply is basically, "People like me prey on people like you, that's how it works."

It gets to a point where the hero starts having doubts about who she can trust and who is truly willing to help her as opposed to help themselves. She's told that she accomplished nothing and everything was handed to her on a platter, that they were both played by their respective bosses (who the CEO suspects is the same person i.e. a high ranking govt official). He breaks down her bravado and confidence.

Finally, the CEO reveals that she was the only kid to be taken from a Brothel because he made a good impression on her. When prodded to explain, the CEO begins to explain in a rather vulgar fashion how much he cherished the night he spent with her. He starts to detail all the stuff she did to him and even goes on to suggest one more session before probably parting forever.

The protag shakes her head in denial and refuses to believe it while the CEO gives more and more detailed descriptions proving that it was he was indeed the "special client" at the Brothel. The protag goes into a frenzy and lunges for the CEO to kill him but obviously gets held back by guards. As she's taken away, the CEO promises he will dream about her beautiful body every night till she comes back to him and laughs at her anguish. He finally declares quite happily, "I'm the architect of your torment! And there's nothing you can do to make it go away." (referring to the trauma she endured)

So, does this work as a final "Fuck You" to the hero for defeating the villain?

Or is it too gross and I should make it more vague, like he's messing with her.

Depends on what you're trying to accomplish- There are no bad ideas, only bad execution of them. So, if the whole Brothel bit isn't what exactly matters & just how she has Issues then be more concerned with her conflicts. However, if changing the Brothel bit significantly changes what you're wanting to write, then you shouldn't be forced to dramatically change your story.

I suppose another thing to consider is to what extents other works do those elements you're concerned about- Both to identify things (not) to do, and what others were able to get away with. Honestly, so long as you're meaningful about what you write (instead of "[Unlawful Sex Act] = Instant Trauma), you'll do fine- Just don't expect Moral Guardians to get it though regardless of craftsmanship.

@Kkutwar

To start with; the Brothel bit is only a small part of my protagonist's backstory, think Wolverine. A collection of events that have turned this otherwise sweet girl into an emotional wreck. However, it is one single ugly experience that comes back again and again to haunt her. She gets called "whore" multiple times by one of the bad guys and she even has nightmares of it.

The CEO detects this this through their conversation and basically uses it as a way to bring her down from her high perch of "YES I HAVE WON! THE DAY IS SAVED".

There is also an alternative I have in mind, my protagonist wants to kill the person who essentially raped her because she feels it will stop the nightmares. She hunts this guy down and finds out he's a pathetic nobody hiding out in Germany getting treatment for his perversions (There is in fact a real life treatment center for pedophilia in Germany).

She wants to kill him and a friend convinces her not too and it takes a great deal of effort for her not to go through with it. It's kind of a growth moment since otherwise she's very causal about taking life. The argument is that the man has suffered enough and living a meager existence as a social pariah and even if he does get cured, will always be an outcast in society. Plus, the protagonist only kills "enemy combatants" so to speak and this guy is a civilian. She's a solider not a murderer.

So now, I am wondering if I can make the CEO be bluffing. He lies to psyche her out and all the information he has was obtained second hand from his cronies who picked her up from the Brothel. So the CEO pretends to be her abuser and laughs in her face that she can't do anything about it. (The CEO is in protective custody). Essentially he wants the protagonist to live with the fact that the man who hurt her so much is alive and well. And rub in the fact that the nightmares and PTSD will never go away. Pyrrhic victory for her so to say.