I can't believe that over the centuries only the bad guys witnessed TOG's immortality. There must have been "good" guys too, and innocent civilians they rescued, who sometimes saw them wake up after they had been killed. People who didn't immediately scream "witchcraft!" and weren't afraid of them (becaus TOG just saved them).
So there must be stories. Told by soldiers and others. Every tavern has that one drunkard who claims to have met TOG. Of course, nobody believes him, but he's a pretty good story-teller, so they like listening to him telling his tales. About a group of 4 immortal warriors, who come to your rescue when you desperately need it. Who save innocent people, help soldiers in need etc. Like some fable told by soldiers to soldiers, with a moral of the story to never harm innocents and TOG will help you if you're in need, but if you do harm innocents, TOG will end you. Every soldier around the world has heard one version of that story or another (no matter if they believe it or not).
I would love some outsider POV. Or maybe some bad guys pretending to be TOG so they can extort people, and the real Old Guard put an end to it (they have to think of their reputation, after all 😁). Or Nile having heard those stories and realizing - huh, you're TOG. Holy sh*, I'M TOG now! o.O