Person A and B were best friends, growing up together until they were teenagers. When they reached 15 (or writer’s choice of age), they were split up by two different royal families of neighboring kingdoms with no heirs and adopted into them. Neither knew where the other went - neither knew how to contact the other.
Some years later (writer’s choice), A is ruling and is on the brink of war with a neighboring kingdom (reasons are up to the writer). Person A readies for battle and marches out to meet the ruler of the opposing kingdom, only to see their old friend, B.
((Bonus: does B recognise them? Do they still fight anyway? Whose fault is the war?))
Honestly at this point I feel like the greatest obstacle to making Ganon stop attacking Hyrule would just be at this point he is probably so incredibly paranoid, it’d be hard for him to take to any proposed ceasefire or treaty- like even before he’s considering ways to twist this in his favor he’s too busy trying to figure out what the other person’s angle is, and the more he can’t find one the more uncomfortable he’d get.
If he could actually believe this is legitimately what they’re offering I can’t see him turning his nose at a perfectly good “can I put down my bow, he puts down his dead sword, and you put down whatever you’re using these days and we nurse our respective trauma in peace” agreement.
Hell, considering where Ganon was in BotW I’m reasonably sure Link could at least get a foot in the door just by making some really good food and tempting him with it, like. when was the last time anyone did any even slightly small kind thing for him.
Like… okay so Zelda, in one memorable incarnation responded to the royalty of a banished Realm Of Forbidden Darkness equated to hell itself showing up at a time where power from said realm was taking over Hyrule by worrying after Midna and making very personal sacrifices on her behalf. She is exactly the kind of person who would worry about the welfare of sealed “ancient godless evils”. She is actually pretty much someone in a good place to be more or less telepathically punched in the face by just how bad Ganon is doing without him even meaning to.
And Link- Link thinks everything looks like friend, pretty much. In BotW he will attempt to tame bears. Literally if you just had him run into Ganon without any of the destiny-and-peril context he is exactly the kind of person who would adopt some kind of shabby demon person he found embedded in a wall by virtue of nothing else that Ganon isn’t doing well.
Link wants to help everyone, Zelda is deeply empathetic and so duty-bound that it would really do her better to be a little selfish for once, and Ganon would logically like very much to not be hurting any more. The cycle is, if anything, a stilted situation that forces them back into their roles and back at each other’s throats, and with very minor shifts in context one way or another they could so easily get along.
And quite frankly… tell me that wouldn’t make the threads of an interesting story.