Berwald and Matthias walk the Field slowly, day by day, time inching by. Sometimes they cross paths with another traveler, or even groups of travelers, the lucky ones. They say nothing as they cross paths (what would there be to say?). nobody knows where they're going, nobody knows where they've been (because there's nowhere to be). Occasionally they'll see somebody they knew (once upon a time before the sun decided to grow), and maybe they'll join up for a while. But eventually Matthias will annoy them with his defiant hope and undeniable insanity, or Berwald will make them angry just because he wants to, and it'll just be the two again.
When they first found each other, they could do nothing but bicker. And that was even when the rest were there (Tino and Peter and Eymund and Vivien), each doing their part to survive and get along relatively well. Tino and Vivien mediated upsets (only between the Dane and the Swede, the only ones around to remember), and Peter and Eymund kept a sense of sweet optimism (the same optimism that Matthias refuses to give up).
Matthias will always thank every god he's ever heard of that he and Vivien were together when the world first went to hell. The scientists had been keeping an eye on the sun for weeks, but nobody truly thought that it would amount to anything (or everybody thought but at least nobody hoped). Of course, as soon as everything flashed hot and bright and deadly, there was no doubt in anybody's mind that nothing was going to end up well. Pools boiled, fruit withered, people fainted, and Vivien cried (xe was strong, but not strong enough for that).
But when they, dragging Vivien's twin (only in body but not in soul) along with them, found Berwald and Tino and Berwald's youngest brother Peter, it was Vivien who was keeping Matthias sane (when xe left, that's when he lost it). Berwald and Tino were absolutely infuriating with their stupid "normal" relationship (or at least as normal as a boy and a transboy could be), Eymund refused to leave Vivien alone (and couldn't perfect Eymund see that it was bothering his twin? Everyone else could), and Peter was a twelve-year-old. Through all this, through all the reasons that Matthias had to hate the world and everything in it, Vivien was always there for Matthias, to help him breathe and stay calm and (don't snap, Matthias, you can't lose it now) stay sane. After Vivien left, after the rest left, all he had was Berwald. And who could stay sane around Berwald?
Tino could stay sane around Berwald. The sweet, much smaller boy made sure that Berwald picked fights only with Matthias (the only one who could take it), even when Peter asked about his binder and insistence to change away from the rest. Tino held him back, assuring him that everything was fine, and that he would explain to the child (but curiosity still killed that cat).
When Tino left, Berwald could barely stop himself from destroying the others. Not that it mattered, eventually they all were gone, and Berwald only had Matthias. And how could he not fight with Matthias?
They fought for weeks, what else could they do? But it soon dropped off (there was nothing to fight about anymore). Really, all they could do was walk, and try to stay alive (the one good thing about all the walking is that now they're in better shape than ever before).
What with the Field being like it is, it feels like they're in that movie that Matthias and Vivien saw together (what seems like centuries ago), the one with that botanist that got stuck on Mars. But they aren't botanists, and they aren't smart enough to become botanists, so they have to live on what they can scrounge up (giant mutated desert rats, dying bushes, what's left in the burned out buildings, which isn't much at all). Berwald is pretty sure everything would be much easier if they were underground, but what are they supposed to dig with?
And so they continue to walk on. Sure, it's boring, but (after what happened the last time they stopped they don't dare) it's better than anything else.
(Matthias can still hear Vivien's sobs as xe slowly turned as bright red as the new Sun.)
(Berwald is haunted by Tino's and Peter's faces as they lose the ability to speak from the dryness of their throats.)
(Matthias couldn't forget the guilt that his arofriend's twin ran away because of him.)
Berwald can see Matthias going. He knows that soon he'll be alone again. Maybe a stop wouldn't be so bad.
They can just go together instead.