Heretic is a tool that allows users to modify language models without training, using a collection of mathematical techniques to steer behavior based on example prompts and scorers. It can suppress censorship, reduce sycophancy, and alter emotional alignment, among other modifications, without requiring in-depth knowledge of language models. Heretic supports most dense models, including multimodal and hybrid models, and has been benchmarked against competing tools, showing comparable performance. Users can configure Heretic using TOML files, with options including suppressing refusals, reducing humor, and altering emotional alignment. This tool can be used on a gaming PC, making it accessible to a wider range of users.