The Depth Fade Sub Shader Node in Unity enhances game development by enabling immersive fading effects based on the distance from the camera, essential for creating atmospheric visuals like fog and underwater distortion. To create a custom Depth Fade Sub Shader Node, begin by opening Shader Graph and establishing a new graph for 2D or 3D rendering. Within the sub-graph, implement the logic to sample the depth buffer and calculate the distance from the camera, then output this value to control shader properties such as opacity. After saving your sub-graph, integrate it into your shaders, allowing for fine-tuning of parameters like distance falloff and opacity thresholds. Utilizing sub shader nodes provides granular control over rendering, fostering advanced visual effects and enhancing player immersion in your Unity projects.