MugenHeart for PC

A new card. A new story.

MugenHeart is a Windows story player. Load a Story Card containing characters, a world, and roleplaying instructions, then continue through text conversations and choices. The AI model is included, so you do not need to assemble an AI setup or obtain an API key.

Three starter cards

• Partner Matching — Simple: Describe an adult fictional partner, your relationship, and a world or opening scene. Play out a romance, everyday life with a friend, or an adventure with a companion.
  
• Ark Mountain: Form a party and explore a dungeon with dice-based checks. The current card appears in the app under its Japanese name, クロックワーク・ブランチ.
  
• Ultimate Battle: Direct a fighter as their trainer and pursue victories in an arena through text-based battles. The current card appears as アルティメットバトルGM.

These are starter cards offering three different ways to play. Load other compatible Mugen Cards to explore other settings. This is not a trading-card or deck-building game.

AI dialogue generated on your PC

After installation, AI conversations work offline. Generating replies does not require sending your conversations to an external AI service, entering an API key, or paying external AI usage fees. Steam downloads, updates, and browsing external websites require internet access.

Keep a record of your story

Continue with conversation history, updated memories, diaries, and save/load features. As conversations grow, older dialogue and diaries are summarized for the AI's input. Summaries may omit details; perfect memory retention is not guaranteed.

Before you buy

The game primarily generates text, not character images or voices. AI replies can vary or contain errors, and perfect reproduction of every card instruction is not guaranteed. Model loading times and response speed depend on your GPU, memory, and other hardware. Please check the system requirements.