Don't be fooled by the somewhat comical quadruple time of the marching, or the uniform, or their smaller stature. The Gurkhas are the most feared regular infantry anywhere.
All royalty is the same around the world. The Gurkhas by pledging allegiance to our monarch, they are pledgin allegiance to their monarch. It’s all same the everywhere. The King of Nepal can take the same salute of the British military in the absence of our monarch etc, so can any monarch around the world but not a government official.