Kray stands out as a cutting-edge global illumination renderer that facilitates swift and precise scene rendering, especially in environments where indirect lighting is crucial. It incorporates the latest algorithms and enhancements, enabling it to efficiently generate comprehensive global illumination effects, including reflections, refractions, and caustics, on standard computing systems. The renderer boasts rapid global illumination techniques such as light/photon mapping, which, while biased, provides impressive speed with minimal dependency on ray recursion counts; path tracing, which is unbiased and employs various sampling optimizations; and irradiance caching, designed for fast, view-independent storage of reusable GI solutions, along with caustics management. It features diverse light models, including point, directional, line, area, background lights, HDR image-based lighting, and the ability to pre-sample lights. Additionally, it supports instancing, permitting the efficient reuse of the same geometry across multiple locations in the rendered scene with minimal memory usage. Remarkably, instanced geometry can even be instantiated further, allowing for self-cloning capabilities with a user-defined number of recursions, making Kray a versatile tool for advanced rendering tasks.