As an average grunt in the Marine Corps, there’s some ranks you just never come across. You’re told they exist, but you only believe it out of faith in the same way you might believe in Santa Clause or Te’o’s dead girlfriend. Some of these ranks are (of course) Chief Warrant Officers above CWO-3, Generals (all), Master Gunnery Sergeant and the E-1 Private. They’re ranks that may as well not even exist as far as the world of the Lance Corporal is concerned. You never see them, they never see you, and you’re probably better off that way.
But seriously, I never once saw a CWO above CWO-3. I doubted the existence of Master Gunnery Sergeant until one PCS’d to my Battalion just a few months before I EAS’d. I don’t know anyone that was a Private in the fleet that wasn’t because of some epic ninja-punch bestowed upon them by some other mythical rank in an office somewhere. Hell, as a Lance Corporal I never met a General until after I EAS’d and was introduced to one at an IRR muster.
These ranks exist in books, but so do minotaurs, centaurs and Gandalf.