What happened after Dream let Ink eat the apples? Owo-
Well, when Dream went to get Ink an apple, he ended up doing the same thing Original Nightmare did- turning all of the apples gold. This resulted in some panicked shenanigans, which...
Ended up in. Ink. Eating/absorbing all the apples. All of them. Not a single one was spared.
And then Ink became something he didn't use to be, and fled back to his brother to Maskswap, but... Dream and Nightmare's part in the story doesn't just end right there.
Now, Nightmare was more than a little unhappy about this. Sure, neither of them took their job seriously, but what the fuck, Dream! At least TRY to not fuck it all up! This resulted into them getting into a fight.
And since they were both lousy idiots, they took it a bit dramatically.
Nightmare refused to talk to Dream, and Dream set out to fix what he had fucked up and find Ink, or Origin, as is his 'proper' name. Nightmare was left behind to guard the dead husk of a tree, surrounded by people who hated him and thought he was the reason all the suffering had happened in the world.
At least, they thought that before they saw Dream help a monster destroy the thing their village was built around. And when the guardian that failed to save the day leaves, the other guardian rises to his place.
And Nightmare became the one the people looked to for answers.
And in response, he tried to fix Dreamtale. Became it's leader. It's smol, young, dark king. Who eventually ran away with two skeletons dressed in oversized ponchos and wearing cat ears for some reason.
...but that's another story for another time.