Riddle of Throwback #1

I've posted this riddle before, so anyone who's already seen it should leave it to the others who have not. Keep thinking and good luck! Who/What am I? Who am I, that I could be one of the three of the one? Forgive me, for I am fragile, and so am I, and I more so than they. I am before him, and he is before me, and after me, and he beckons me to his chambers all the same. I stand at the ready, at all times, and only through me will he return from nowhere to another nowhere. Winner: ShawShank Answer: VoG Gatekeepers I expected a quick one this time. The next one will be a bit harder. And the one after that harder still. And the one after that...