Show HN: Yuanzai World – LLM RPGs with branching world-lines (yuanzai.world)

We built a simulation engine (currently on iOS & Android) that allows the community to create and share text adventures populated by multiple LLM-based agents. Unlike standard chatbots, our focus is on community co-creation—users define the worldviews, and our agents (with persistent memory and social relationships) bring them to life.

The cool part:

We implemented a system we call "World-Line Divergence" (inspired by visual novels like Steins;Gate). Usually, AI RPGs feel random or infinite loop. We built a state machine that tracks "World Deviation." If players interact with NPCs in specific ways (e.g., convincing an artist to change their style), it triggers a graph switch, leading to a completely different generated ending, effectively breaking the original script.

Tech Stack:

- Backend: Python / Java with a custom AI orchestration framework (to handle agent concurrency).

- Models: Hybrid routing between Gemini, GPT, and DeepSeek (optimizing for cost/performance based on task).

- Vector DB: Milvus (for handling long-term agent memory).

We are currently live on App Store and Google Play. Since it's a mobile-first experience, the link leads to our landing page where you can see the demo flow.

Would love to hear your feedback on the "World-Line" concept: Does this state-machine approach solve the aimlessness of AI RPGs?