I am unlikely to implement full arcs that are based on you meeting a sexy bad end. I don't think there's anything wrong with them as an idea (and perhaps, later on, the mod community will step in to fill that gap)
It's interesting that this topic of how to continue a story after our character has been hypnotized/brainwashed has come up. I myself get annoyed when being hypnotized leads to a bad end and there is nothing after it, but it can be really hard to write a compelling story when your story can be derailed by being turned into someone else's slave. It's one of the reasons why, if you are going to have mind control in your game, it has to be planned ahead. If you don't it causes the author to have to write a whole separate story just for the mind control.
Thus far I have thought of three ways to make this happen.
1. The mind control is part of the main storyline.
Your character is going to be hypnotized and controlled by the enemy, there is no way out of it. You might find a way out of it near the end, but for the most part your character being mind controlled is going to be part of the story.
2. Your character can complete the main storyline working for the protagonist faction, or working for a hypnotic mind controlling antagonist faction
In this case, something is happening that both the protagonist faction and the antagonist faction want to prevent/control/ect.
Let's say there is an evil god that is trying to open a portal to your world that will cause the end of the world. You are the chosen hero who can stop it. There is another cult that wants to stop the end of the world and use the powers of the evil god to take over. If you stay with the protagonist faction, you get the standard good guy ending. If you fail a certain side quest, or a main quest with the evil cult, they capture you and brainwash you into working for them. Now you have the exact same goal of stopping the evil god, but you also have the added goal of helping the cult take over the world. Some of the cult related side quests can even involve capturing your former team mates and hypnotizing them as well.
3. You character is hypnotized by an NPC who has little or nothing to do with the main plot, but needs you to complete your original mission anyway.
Let's go with the previous end of the world example. Your character just happens to be going along and runs into a NPC who finds a way to hypnotize your character. The NPC either knows the importance of your character and their quest, or finds out after your character is their mind controlled slave. Either way, in order to save themselves, they order you to continue on your mission while still serving them. This could range from something as simple as acting as their enforcer for criminal activities all the way to lewd acts. After the main quest is done, and you are no longer needed to save the world, the NPC either keep you as a spy in your original faction or brings you over as a full time slave for them.
Depending on how much work you want to put into the story, you can have it as a simple loyalty swap and they obey the enslaver without question or you can have how the main character reacts to being mind controlled as part of the story. Are they fully aware that they are mind controlled and actively trying to fight it or find ways to escape? Are they more like a sleeper agent, where certain key phrases or images trigger them to fall back into trance were they become completely obedient to the orders they are given? Is it a slow process where the control is deepened over time and the more orders the player has the character obey, they further under hypnotic control they go?
Anyway, just a minor rant from me on the topic. I'm enjoying this game thus far and look forward to the next update.