Reflective DLL injection is a library injection technique in which the concept of reflective programming is employed to perform the loading of a library from memory into a host process. As such the library is responsible for loading itself by implementing a minimal Portable Executable (PE) file loader. It can then govern, with minimal interaction with the host system and process.
Source code referred in this video: https://github.com/stephenfewer/ReflectiveDLLInjection
Other Reflective Loading Technique :