Nyxus

Nyxus is a text-based, AI-powered RPG engine—like playing D&D or Pathfinder solo, just you and the GM.

Your API key, no Nyxus paywall
Nyxus needs a Google Gemini API key (free to create in Google AI Studio). That’s how the app runs without a Nyxus subscription or in-app credits. Heavy play can hit Google’s usage limits on the free tier; limits are time-based—if you see a quota error, wait a bit and try again. Optional paid billing on your Google Cloud / AI project raises quotas; it’s not required to use Nyxus.

No ads
Nyxus is ad-free.

Master your own myths
Nyxus uses Google’s Gemini models to turn your ideas into worlds and sessions—whether you’re an experienced GM or a solo player building one character and one story.

Lore upload — your world, your rules
Bring your setting to the table: upload PDF, plain text, or Markdown so the GM can lean on your factions, history, and geography—not a generic default setting.

Tabletop-style play

Character sheet: HP, AC, gold, XP, and inventory update from the GM’s structured updates as the story moves.
Dice tray: When the GM asks for a check, roll d4, d6, d20, and more—with fair or “favorable” dice modes in settings.
Quests & codex: Track quests on their own tab; browse NPCs and lore you’ve discovered in the Codex.
Sight & sound

Scene images: Generate AI illustrations of the current moment (your key, your chosen image settings).
Narration: Text-to-speech for the GM’s lines; audio can be saved per message. Background music and SFX add atmosphere.
Creative control

Undo last exchange: Take back the last player + GM turn from the toolbar.
Retcon: Long-press a GM message to edit the text and rewrite continuity.
GM mode: Add director instructions that steer the model without showing in the main chat.
Export: Save the story as a PDF, optional campaign JSON, or a single narrated audiobook file (.wav)—from the in-game menu.
Privacy & AI
Campaign data, generated images, and audio are stored on your device. Nyxus does not run its own account system for your campaigns. Using Gemini means your prompts and related content are sent to Google’s services under Google’s terms—see Google AI / Cloud documentation for details. The app includes a short guide to creating your API key.

Infinite stories. One engine. Welcome to Nyxus.