A fundamental aspect of the Genode OS project always was the support for various kernels as back-end. It remarkably raised testing versatility and provided a high flexibility to users and developers. But supporting the Genode API on self-contained third-party kernels is sometimes also accompanied with deficiencies, redundancies, or work-arounds. To also have the option of a basic kernel without such compromises, the custom Genode kernel was developed. Its main distinguishing mark may be that it not only trusts the Genode Core-component but even more is a mere library to it. The implications of this new design and other characteristics of the custom Genode kernel, such as scheduling, capabilities, and ARM virtualization, are discussed in this lecture.