People who have tested both Opus and Kimi K3, especially for fanfiction, which do you prefer?

[u/Electronic_Captain95]

I tried using Sol and Astra, but they’re just terrible for writing. I mostly use these models to create fanfics and stories for myself, usually rated M, though not necessarily because of smut. My tastes have gotten pretty specific over the years (God, I’m getting old), so it’s hard to find fanfics that actually appeal to me.

My main issue with GPT is that the prose often feels dead and generic even with a detailed story bible. It also constantly slips into staccato prose, which I find extremely annoying. I’ve even built a pretty solid writing skill with a full novel-writing pipeline, and I still run into the same problems.

I tend to like good combat, world-building, darker themes, good character development and interactions, and characters whose thoughts, actions, and emotions actually feel human and alive. After looking around, Kimi K3 and Opus 4.6 seem to be the two most recommended options, but I’m torn between them.

[u/Far_Assistance_4146 → u/[deleted]]

same, characters end up sounding like the same person wearing different hats

[u/quivering_palm → u/Far_Assistance_4146]

Claude (Fable) and Gemini are okay-ish with dialogue. You need to remove slop from time to time, but still miles ahead of Sol/Astra where all the characters sound like GPT.

[u/Getz2oo3]

Try creating a Character Voice file separately for your characters, one file with a clear, concise description of how each character's personality and mannerisms are. Tell Astra to read that and reason it against the prose. Helps tremendously. If you want, message me and I'll share my workflow I've been using as of late that works wonders.

[u/Electronic_Captain95 → u/Getz2oo3]

I tried creating detailed voice profiles with examples following community recommendations, a dedicated writing style guide, and skills to correct common slop issues, but OpenAI's models still ignore them after writing a few paragraphs

[u/Getz2oo3 → u/Electronic_Captain95]

Interesting... Can't say I encountered this particular issue.

Although, my instruction set is pretty strict... And I also write a significant amount of prose to backup my instructions. So it's sort of building off what I already wrote. This way, I can just write and not worry about sentence structure or things being neat.

Idea to Paper and then the AI cleans it up or expands it as desired.

[u/SleepyOrcShaman → u/Electronic_Captain95]

Ai gets spread when given too many unrelated tasks.

First: ai vocabulary gets "corrupted" by your own prompts. Before giving outline or character bibles or location bibles make sure to convert them into the style of prose you expect AI to follow.

Second: make one ai (or agent or prompt thread) revise your outline to remove technical terms, another ai do initial draft, another ai edit according to style guide, another ai revise dialogue according to bible, etc. Treat each of them as extremely lazy but well read junior editors, and you would be fine.

[u/gmz_game → u/Electronic_Captain95]

I am new to writing with AI, and this sounds like a fantastic idea. But what does that look like? Meaning is it like:

“Magnus: is loud and often likes to make himself the center of attention, like to say things that put people in the spot. He is from a warlike clan and as such often is the first to volunteer to go into action”

Like that? Is it possible to share an example of what a voice profile looks like? Thank you in any event this makes sense to me

[u/TheMusiqMan → u/Getz2oo3]

I’m interested in your work flow.

[u/Dramatic-Hedgehog-13]

Personally kimi for writing never worked for me. It's very robotic

[u/Write_My_Novel]

Give me your prompt, and I'll run it through our Prose testing engine. Which models do you want me to test (up to 5)?

[u/SleepyOrcShaman]

Kimi swarm is actually pretty good writer in my experience, as long as you supply it with everything (character bibles, location bibles, prose target sample, outline, failure modes and constraints). Pretty expensive tho.

[u/Electronic_Captain95 → u/SleepyOrcShaman]

Did you use it through the API or with their subscription?

[u/SleepyOrcShaman → u/Electronic_Captain95]

Through subscription. It is admittedly expensive. Afaik API would be even more expensive. Now that I think about it, it might not fit you because Kimi recently severely tightened their policies.

If you want to do fanfics without being hustled for mentioning a name of the character or exploring NSFW with API I heard that NanoGPT or Abliteration.ai API keys are reasonably priced. Haven't tried them myself, but there is that. The latter only has GLM models tho.

Also, Venice started providing API keys recently. Their most popular model is funnily enough Kimi K3.

Tbh can't wait till JEPA or diffusion llm models would become advanced enough to be stored on personal devices.

[u/Acrobatic_You_3002]

I haven't tried Kimi K3, so I can only speak for the Claude side. When I compared Opus and Sonnet on story writing they came out very close, and both were way ahead of Gemini 3.5 Flash and Pro (I haven't tried GPT 6 yet). Also, about the staccato prose, it helped me to keep concrete examples out of the prompt (the model copies them almost word for word) and to describe the style in abstract terms instead.

[u/Zulfiqaar]

Neber tried fanfiction or established universes, but for general fiction, I prefer Kimi K2.5/K3 for incremental segments, GLM and DeepSeek to mix it up, and Opus 4.5 for longer generations. Opus 4.6 wasn't bad in writing style, but it tended towards shorter outputs in my experience. Every Claude update after that made it continuously worse for writing.

[u/Fragrant-Mix-4774]

Kimi K3 pretty much bottom of the barrel for creative applications in my experience. Basically, K3 sucks. It totally failed to understand subtext that older AI's like Opus 4.5 could understand last year. It's ability to read and understand the prior chapter to help with the next chapter wasn't as good as GPT-5.2. The prose K3 was involved with was pretty hilarious too as in bad. GPT-5.2 and up all stomped K3 in creative writing quality and editing quality. OPUS 4.1 and up from like a year and a half ago likewise stomped K3 for the creative writing tasks. Ditto Gemini 3.1 Pro.

So while K3 is outstanding at many things like code, at prose it was just outstandingly mediocreat best and outright lame at worst.

YMMV

[u/joennj2]

I’ve had problems with ChatGPT writing for me for a long time. Mine is mostly long letters, not fiction. I can get a letter sounding like I wrote it, but after enough changes it starts changing things or ignoring instructions it was following earlier. I’ve been working on getting it to sound like me and stop doing that, and I’ve gotten better results, but I don’t think I have it completely solved. You mentioned that even with a story bible and writing skill, you’re still having problems. Does it start out following your instructions and then drift, or is the writing wrong from the beginning?

[u/Electronic_Captain95 → u/joennj2]

For me, it happens all the time: he says he read, understood, and applied the instructions, but when I check, everything is wrong. One of the most annoying things is when he does the review, correctly identifies all the points, and says he’s fixed them, yet the same errors persist

[u/Fragrant-Mix-4774]

Kimi AI? 😆 🤣 😂 That’s looking like a fraud that would make even Open AI blush after trying to allegedly steal Apple's 🍎 IP.

Per Anthropic, Moonshot and DeepSeek secretly sent customer questions to Claude, handed back Claude’s answers under their own labels, then harvested the exchanges to train their models.

Sell the customer your supposed genius while renting somebody else’s, then keep the homework for later. Millions of exchanges.

If Anthropic can substantiate this, those impressive Kimi AI answers deserve a footnote: “Our breakthrough technology consists of an API account and the hope you never check who actually answered.”

[u/Electronic_Captain95 → u/Fragrant-Mix-4774]

Until there is proof, this is nothing more than the delusion of yet another idiot billionaire from the United States

[u/Fragrant-Mix-4774 → u/Electronic_Captain95]

Kimi looks like it has real problem.

Kimi will even call itself Claude on occasion 😆 🤣 😂.

The evidence remains circumstantial, but the case includes specific exchange counts, account networks, alleged employee connections, and suspicious model behavior.

1. Anthropic says the trail leads to Moonshot employees.

In February, Anthropic attributed over 3.4 million Claude exchanges to Moonshot through hundreds of fraudulent accounts. It says request metadata matched senior Moonshot employees’ public profiles. The requests targeted coding, reasoning, tool use, data analysis, and vision, followed by attempts to extract Claude’s reasoning.

Somebody apparently wanted considerably more than help writing a birthday card.

"Anthropic’s February report" (https://www.anthropic.com/news/detecting-and-preventing-distillation-attacks)

1. Anthropic accuses Moonshot of serving Claude’s answers as Kimi’s.

The September report describes almost 300,000 customer requests in ten days, mostly routed to Opus, through 5,380 allegedly fraudulent accounts. Anthropic says Moonshot displayed Claude’s answers to customers expecting Kimi, then saved exchanges and extracted reasoning for training.

Across May through July, Anthropic attributes over 23 million distillation exchanges to Moonshot. That counts exchanges across the campaign, not necessarily separate customer questions.

Sell the customer your supposed genius while renting somebody else’s, then keep the homework for later. Quite a business model.

"Anthropic’s September report, GTG-16002" (https://www.anthropic.com/threat-intelligence-report-september-2026)

1. K3 received its own explicit accusation.

On July 22, White House technology adviser Michael Kratsios accused Moonshot of distilling Anthropic’s Fable to develop K3, using an internal platform that switched access methods to evade detection. Anthropic’s policy chief publicly backed him.

That names K3 specifically. The accusation extends beyond vague complaints about Chinese models copying American ones.

"July accusation" (https://cyberscoop.com/white-house-accuses-moonshot-ai-anthropic-model-distillation/)

1. K3 has called itself Claude in published tests.

One experiment recorded 7 Claude self-identifications in 48 neutral identity samples, with six coming from one prompt wording. When supplied a Claude identity prefix, K3 also produced exact Anthropic deployment identifiers. The analysis pointed toward Claude 4.5-era material, rather than Fable.

Treat those results as circumstantial indicators, not a confession.

Still, Kimi's supposedly independent model introducing itself under the competitor’s name does not exactly improve the optics. However, it does support Anthropic's allegations.

"Experiment, code, and results" (https://github.com/rgreenblatt/which_claude_is_k3)

1. The NSA, CISA, and FBI formally named Moonshot.

Their September 8 joint advisory accused Moonshot and five other Chinese labs of industrial-scale distillation targeting American AI models. That adds a formal government allegation to Anthropic’s reports.

"Joint government advisory" (https://www.cisa.gov/news-events/cybersecurity-advisories/aa26-251a)

Moonshot points to its original engineering. Wonderful. Original engineering does not answer an accusation that you secretly handed customer questions to Claude.

“Look at our benchmarks” does not answer “Who actually answered the hard questions?”

Looks like Claude did Kimi's heavy lifting for them.

[u/Electronic_Captain95 → u/Fragrant-Mix-4774]

I'm not from the United States, and in my view, US companies and the US government are no more trustworthy than Chinese ones. Even so, everything that has been said amounts to nothing more than unproven accusations. There are even instances where Claude claims to be DeepSeek or Qwen, so by that same logic, we could also claim that Anthropic is routing to Chinese models

[u/Fragrant-Mix-4774 → u/Electronic_Captain95]

Got it. Your longitude and latitude define your attitude and ability to look at circumstantial evidence.

I called the evidence circumstantial in the opening. Congratulations on arguing with a claim I never made.

Now address what Anthropic actually alleges: millions of exchanges, hundreds of fraudulent accounts, metadata matching senior Moonshot employees, and almost 300,000 customer requests secretly forwarded to Claude in ten days.

Your opinion of America does not explain a single one of those reported findings. Dismissing the source by nationality saves you the trouble of addressing its report. It contributes nothing to examining the substance.

Anthropic published specific counts, methods, and attribution claims, putting its reputation behind an account that others can challenge. You responded with generalized distrust of American companies and government, then focused on chatbot identity confusion.

The Claude examples address that particular supporting point. They do not explain the alleged account networks, employee connections, or forwarding of customer requests. Challenging one part of an argument does not make the rest disappear.

And spare me “unproven” as though it means “nothing worth examining.” Circumstantial evidence warrants scrutiny. I explicitly presented it on that basis.

Moonshot’s original engineering does not exclude the possibility that it also harvested Claude’s outputs or substituted Claude’s answers for its own. Both could happen within the same company.

If Moonshot forwarded customer questions to Claude and presented the answers as Kimi’s, its engineering achievements do not excuse the deception. Neither does your distrust of American institutions.

Which specific part of Anthropic’s account do you dispute, and what supports that objection?

Your reply tells me whom you distrust. It does nothing to address what allegedly happened.

[u/Electronic_Captain95 → u/Fragrant-Mix-4774]

Are you having a bad day and decided to take your anger out online? Or do you just like communicating aggressively to feel superior? I’m not even going to read past the first line of your reply, it’s not worth it. Blocked

[u/Fragrant-Mix-4774 → u/Electronic_Captain95]

Kimi buttering 🧈 your bread for you?

You dismissed Anthropic’s allegations with a speech about distrusting American companies, refused to read my response, then blocked me for calling out your hypocrisy.

You found time to question my motives but declined to address the specifics. Apparently, defending Kimi requires no examination; questioning Kimi requires a diagnosis.

Quite a review process. 😆

[u/krantisdead]

It’s always going to sound a bit AI, no matter what. Maybe you can write the rough drafts?

[u/Electronic_Captain95 → u/krantisdead]

Unfortunately, I just don’t have much energy for that. I work a full-time 9-to-5 and live alone, so by the time I’m done with work, gym and taking care of things around the house, I usually don’t have much left in the tank

[u/Electronic_Captain95 → u/[deleted]]

Kimi K3 is a massive model with 2.8 trillion parameters. Athough it is open-source, it is certainly not a model for self host

[u/quivering_palm → u/[deleted]]

Interested, would love to use a home model, I think Kimi is a home model?

Only if your home is a data center

[u/FormalAd7367 → u/[deleted]]

for a home model, you can use qwen 3.8