Have you ever heard of this story? It's said that they're are monks who live in the remote forests of Athos, making their appearance here and there to other monks or pilgrims occasianally.
Some say they are 7 some say 12. They pray non stop for the world and when one of them dies, another monk from Athos takes his place. It is believed that right before the events of the apocalypse begin, the invisible monks will climb to the higher mountain top of Athos and do the last liturgy there, that will sigh the end of times.
It's an athonite tradition apparently, Saint Paisios had also speaked about them