I'm sure most RDR2 players have heard the sentence "help a blind man wiil you?" followed by a creepy prophecy at least once in their playthrough.
In a way, he's very similar to the strange man from RDR1 one;
both are odd characters who seemingly know the future of John and Arthur.
A great deal of the man's quotes directly refer to Arthur's ending;
"Your whole life has been one of regret, but it can end better than it began"
"Bad news await you, sir. Sadly, sooner than you think. But beyond the news, paradise awaits. paradise.."
"That which is killing you will help you finally to see. And see clearly friend, see and hear"
"Do not sleep too deeply, friend, for the man with no nose is coming for you"
"Make your final moments your best moments, sir. Know glory and forget about shame."
"I see the sorrows, and see them clearly, sir. Even when all reason is lost, and all truth has become a lie, you will stand firm. For loyalty is both your saving and your curse"
Another great deal refers to Arthur's character and development;
"I sense great confusion in you, sir. Great confusion. Not because you do not know, but because you are afraid of what you know"
"Just as evil begat evil your whole life long, so good may begat good"
"You keep hidden all that matters, sir, maybe even from yourself"
"You are not who you think you are, sir, which is lucky"
However, the most interesting ones in my opinion, are the vague ones;
"Run from the seeker, sir. Run and keep running, or help others to run"
This is a reference to a very minor detail in the game - when Dutch comes face to face with Milton he tells him "I am nothing but a seeker", to which Milton replies saying Dutch is nothing more than a killer - Both hinting at the fact Dutch's leadership will end in bloodshed and force Arthur to turn against Dutch in order to help as many gang members as he can.
"Your father is seduced by the one with the forked tongue. It's no use hoping"
This is a clear reference to Micah whispering in Dutch's ears.
Despite Arthur's attempts, even at his final moments, Dutch could not be swayed from Micah's way.
"Be warned sir, be warned. Surrounded by fields of burning fire and flesh, the devil will make his sacrifice"
This one in my opinion, is the most interesting one. It could be refering to a few key points in the story;
The first one is when Dutch abandones Arthur in My Last Boy -
In that moment, Arthur is indeed surrounded by dead bodies (hence the "flesh"), and Dutch makes his final choice, leaving Arthur in favor of Eagle Flies and Micah. The burning fire part, could be refering to Arthur's feeling of betrayal, anger and confusion towards Dutch.
It could also be refering to the quest Red Dead Redemption;
As we know, Arthur suffers from low self esteem and views himself as a generally bad person, even after his change in chapter 6.
When Arthur forces Dutch and the gang to make a choice,
he makes his sacrifice - the gang and the life he knew for the people he can protect, as well as sacrificing himself on the mountain so that John could live. He is the devil in this prophecy, sure, he tried redeeming himself, but at the end of the day he's still a bad person who's done horrible things.