Aion 3.5 is a specialist, not a general assistant: AionLabs builds it for interactive fiction, character roleplay and long-running stories. Each response comes from a collaborative process in which multiple specialised models built on the GLM family contribute, and the lab tunes it to keep narratives tense, with conflict, crises and darker themes rather than bland, agreeable prose. It supports reasoning effort and tool calls through the API, has a 262K-token context window (32K output) for long story histories, and is text-only. It is sold through OpenRouter at $3 input / $6 output per million tokens; there are no open weights. For coding, analysis or factual work a general-purpose model is a better choice.