@gayaccount
I'm not familiar with LLM for text generation since I just run image generation/editing for now.
But a quick search brought me to some old reddit posts
https://www.reddit.com/r/LocalLLaMA/comments/1dkw79c/current_best_storywriting_local_llm/
And
https://www.reddit.com/r/ChatGPTNSFW/comments/16fny83/easy_offline_llm_for_making_very_graphic/
With https://www.reddit.com/r/ChatGPTNSFW/ being specifically for using GPT for NSFW content. The posts there may not be talking about local generation, so check and see and/or ask directly
Since the above are older threads, the models cited may be outdated now. Given the pace of how quickly things have been advancing, it's a good idea to always check if a model has been updated, abandoned by it's coder, or replaced with a more effective/different model.
LM Studio (https://lmstudio.ai) is a common recommendation for installing, running, and interfacing with local LLMs. I'm not doing LLM/story/bulk text generation, so I can't testify how good it is. It seems to be mostly for agents, but it kept coming up in my searches for running local LLMs.
Perchance is also able to create an image of a character from the image generators, and you can directly pipe that into an LLM character chatbot without leaving the site. Given how it can create pretty much anything on the Image gen side; the text generation is probably equally as liberal, provided you're willing to learn how to structure your prompts
For whole stories they also have a story generator (https://perchance.org/ai-story-generator) and you can save that story offline and potentially use it as context/training for later use
If you want a "live chatting with a character" experience, they have that too, and their official image generator (and most custom ones) can export a character image directly into a character chat generator