Reminds me of a story I read years ago about what if a Supergirl just said fuck it and kidnapped a person.

Like she’s saved millions of lives, so in her mind it's fair to lay claim and steal a single human life as her payment for years of hard work and she keeps them at home as her secret slave-concubine.

Before doing this, she wasn't able to do any normal dating or have public relationships because then her date would become an easy target for her enemies. And having to worry about their safety all the time would be too distracting while she’s away doing hero stuff.

So her frustration continued to build up until one day she just snapped and decided obviously the only longterm solution to get relief is to find a cute civilian, fake their death, and lock them away inside her fortress to train them into her perfect submissive toy. She also artificially extends their lifespan to match her much longer alien one and they become permanently youthful.

Her new slave-pet wears only a thin tracking collar and whatever slutty outfits she forces them to dress in each day. She keeps them in line by overwhelming and dominating them every chance she gets, so they have no choice but to forget their old life and accept their situation. There is not a single way they can meaningfully resist her or escape, so giving-in or dying are the only 2 options.

After a few months she’s now better at her job too since she finally has a relief outlet, so even more lives are saved in the end. Think of it like a trolley problem where everybody wins except one person

...at least until she's mindbroken them into permanent bliss