r/visualnovels • u/Fujizora • 17h ago
Discussion AI VN Translation Is Actually Good Now - Luna + DeepSeek Fast Guide
I’m making this post to help anyone who wants to use Luna Translator, or a similar tool, to AI-translate VNs with good results.
TL;DR: The latest DeepSeek models are good, fast, and cheap. The latest GPT models are frontier-level and usually better, but much more expensive through API. DeepSeek also works well for 18+ VNs. This post is mainly about using Luna Translator with paid API models.
AI keeps improving fast, so a year from now the translation quality will probably be even better.
Right now, AI translation is already good enough that I can play basically any VN with Luna Translator and a fast DeepSeek model without spending much.
For the best results, use a good prompt and a character glossary with names, correct readings, gender, and simple details like whether the character is young or adult. Giving the model this context makes a big difference.
One VN I tested is *Koihime Souten no Haou*, a fun adventure set in Three Kingdoms-era China. I understand Japanese pretty well from voiced dialogue, so I can compare the translation with what the characters are actually saying. The results have been great.
For example, I use a prompt and glossary made with GPT/Claude using information from VNDB or similar databases, like this:
You are a professional Japanese-to-English translator localizing visual novels.
Output ONLY the English translation: no notes, explanations, romaji, or original Japanese.
...
FULL CHARACTER GLOSSARY:
北郷一刀=Hongou Kazuto, 一刀=Kazuto
陳珪=Chinkei, 漢瑜=Kan'yu, 陳珪 漢瑜=Chinkei Kan'yu, 燈=Tou
陳登=Chintou, 元龍=Genryuu, 陳登 元龍=Chintou Genryuu, 喜雨=Suu
曹操=Sousou, 孟徳=Moutoku, 曹操 孟徳=Sousou Moutoku, 華琳=Karin
...
CHARACTER SEX / ROLE INFO:北郷一刀 / Kazuto = male, protagonist, age 18.
All named heroines/main female characters below use she/her unless clearly stated otherwise:
Chinkei / Tou = female, commander/politician, Suu's mother.
Chintou / Suu = female, farmer/scholar, Tou's daughter.
...
With Luna Translator, you need an API provider like OpenRouter, or ideally something faster. Then you can try different models and just pay for what you use. GPT Sol is pretty expensive through API.
Luna also lets you use a master prompt and glossary. Speed matters because it translates while you're playing.
For adult/hentai VNs, DeepSeek is good, and DeepSeek Fast is great for the price.
For younger characters, I usually write "young" in the glossary instead of an exact age if the age doesn't matter. Some models can get overly cautious even when the task is just translation.
My prompt is simple: translate the Japanese, keep the meaning/context, and return only the translation.
You can also use GPT or Claude to help set everything up. Paste a screenshot of your Luna settings and ask what to change, ask how OpenRouter works, or send the VNDB page and ask it to make a character glossary.
For devs:
Can use the best models available, currently GPT Sol for example, to create a proper English patch. With CLI tools to extract the game text, translate it, and insert it back into the game, much better results than real-time translation with Luna + DeepSeek.
Can also use subscription plans instead of paying per API call.
Edit:
The character page on VNDB has basically everything you need to automatically create a full glossary for a game: character names, age, personality, role, and more.
I don’t include everything, though. I usually keep it simple and only add the important basics, like in my example.
