My Nightmare and Dream Headcanons:
I've always had a vision of how I personally like to think happens after the apple incident. It makes the characters more enjoyable to me and allows me to have fun with the beloved twins of the fandom. Feel free to read and tell me what yall think! And sorry in advance at how rambly it is :3
After Nightmare destroys the village and kills everyone, with the exception for Dream of course, he goes on to reek havoc across the multiverse. The negativity consuming his mind makes him crave more negative energy to keep him strong and powerful. He destroys, kills, tortures, etc. in every new AU he finds himself in, his abilities being strange and varying from all sorts of things that will be listed over time (but an example would be turning those to stone like he did with Dream). With some much excess negativity he seemed like he could do almost anything be desired. He was basically a god to everyone that he came across.
Eventually, Nightmare desires a place of his own. He does think about making Dreamtale his place of rule but he no longer wants to be in that dead village, even if he renovates it. So, he instead finds an unfinished/unoccupied AU that appears to be some sort of dead waste land like place. The vegetation is all withered and void of it's vibrant colors, the soil is dry and rough, the sky is always cloudy, hardly ever showing the sun or night sky. Here in this isolated AU he begins to build a castle out of his negativity.
Although Nightmare is a bit crazy and on a negativity high during this time, Nightmare is still himself in a way. Why does he make a castle? Because Nightmare use to read story books, ones about fantastic journeys, fairytales, most including some sort of description of castles. And he always loved the idea of living in a castle before the incident. Castles were always a place of luxury and comfort. As a person who lived under a tree, a castle was a dream home to have. And he could make it a reality here!
It grows over the years of him slowly building and morphing it to the way he desired. The one thing that I like to add to this idea is that the castle shifts and changes to any outsiders the castle is not familiar with. Though it does not actually shift and change, it just feels/looks like it to the person as the castle leads them around to random parts of the castle. That way, if anyone who manages to find his little area of the multiverse, they will not be able understand the layout. He does move Dream over to his castle as well. It was mostly for him to gloat over his victory over what happened but deep down he actually just didn't want to leave his brother in what was left of their old home. But he won't admit that now hehe.
With his castle he also gets his King complex. Coming from the treatment of the village, having the status of King and being seen as above all others fuels his negativity filled self to never be at the bottom ever again. And as a King, he needs an army. He did struggle with this as he wasn't exactly sure what form to give them. A small part of him thought about making a replica of his brother but that was quickly squashed a moment later. He ends up making Papyruses after learning that that is the actual counterpart of what his body was made after.
Nightmare is entertained by his army for a while as he continued to have fun around the multiverse but eventually grows tired of them over the next couple hundred years. Not to mention, having to constantly rebuild his army whenever they were damaged took a lot of his negative energy so much so that it started to lowkey affect him. That was something that had never happened to him before and he ended up deciding the army was a waste of time and effort on his end.
In fact, Nightmare had grown bored of quite a lot of things over the years. His terrorizing began to feel more like a chore. It was no longer fun. Sure, he still got fueled by the negativity he caused, but it no longer gave him satisfaction. It was always the same when he went and it became mundane. Even when he came up with new ways to feel that thrill he had at the beginning, it never lasted for long. So, he began to find new ways of entertainment, ways to past the time.
This caused him to actually pick up and drop a lot of different hobbies. Reading was something he specifically picked up quickly, almost forgetting he could enjoy a good book for hours on end. And thanks to the access of the multiverse, there was plenty of books he could simply take and read. This becomes the start of his vast library he ends up having in the castle. Then he goes through a variety of other hobbies, ranging from cooking to origami. Anything he tried once to see if it could keep him busy without making him feel like doing literally anything else. He does end up gravitating towards more artistic forms of hobbies. One he especially likes is making stained glass art. Although he liked the dark and gloomy vibe his castle gave, he did find it lacking some things. So he tried making stained glass pieces. They weren't perfect by any means but with enough practice he began to enjoy it and create art depicting himself and things relating to him. In the far future his castle would be adorned with his stain glass art in several areas of the castle, mostly his library.
Along with his hobbies he also becomes interested in the multiverse itself. Wanting to learn it's intricacies and the AUs themselves. So, he begins to document what he observes about the multiverse. At first, they were normal documents, simply listing information in an organized way but Nightmare became unsatisfied with it. Having to reread through a slug of long winded information dumps that he wouldn't want to remember on his own. This causes him to change the way he documents AUs. He still keeps it rather organized and still includes sections for information about the AU before the rest of the documents become diary entries.
I love to think Nightmare use to have a small diary he would write in back in Dreamtale before it was probably taken from him by the villagers. Despite what happens to said diary afterwards, he did enjoy writing down his thoughts and feelings because he never got to express them to anyone. So with these diary entries in his documents they are essentially of his own thoughts and opinions of the AU. They also document his visits/memories of the AU. Most of the time, he just stalks the AU and watches from afar but sometimes he uses his magic to change his form to blend into the crowd. Though it wouldn't exactly last very long due to his negative aura. Most wanted to stay away from him. To solve this issue, he taught himself to conceal his aura by keeping himself/his emotions calm. It wasn't always perfect, it would slip out occasionally if he wasn't too focused on it. Later down the line he is able to control it very well, almost like an off and on switch. But it does slip out of he happens to get very upset (which doesn't normally happen in the far future).
Over the next couple of hundreds of years, he creates a whole archive if information he's learned, leaving the multiverse to build itself as well as causing him to slowly mellow out. The negativity in dwindling down inside of him and allowing himself to think more like his previous self. So much so that he began to visit Dream more often. He has done so occasionally in the past but only briefly to sort of reflect and reminisce. He wouldn't have admitted it before but now he could.
Nightmare missed Dream. He missed his brother dearly. He missed having company. He was lonely (keep in mind he does get Killer at some point after this but even then Nightmare struggles with interacting with another person and his negativity causes him to still be a bit cruel towards his first subordinate). And it was with these more frequent visits Nightmare realizes that, even if he wanted to, he couldn't have Dream by his side anymore. With his more cleared out thoughts, he realized that the Tree of Feelings, their mother, was gone. You would assume the balance it maintained would presumably had faded and caused the multiverse to go into more chaos, but it didn't. It was still there, because Nightmare and Dream were the new balance. They both Guardians of the tree and only became intertwined with the balance forever once they ate their respective apples. The balance, despite the chaos and havoc he's caused, hardly ever broke. Because Dream was still alive.
At this point of time, Nightmare could feel that his once powerful negative energy was going to fade within time. So, freeing Dream would be a now or never thing. And when he did, he scared off Dream out into the Multiverse. Making himself out to be the "villain" of this story and telling Dream off.
Nightmare does this because he doesn't really think he deserves to be in Dream's life anymore. He's done too much to the multiverse to simply live happily with Dream. And Dream deserved to live and learn about himself. Be his own person like Nightmare sorta did that himself over the 450 ish years he's lived on his own. And not to mention, Dream needs to fix what he's done as the other side of the balance. Dream needs to be the Hero. Even if it means they can never be together as brothers anymore.
His plan is very flawed. And as much as I love that Nightmare is pretty smart, wise, and knowledgeable through his own years of experience, he's not good at everything. I like the idea that he can be a little dumb because he's both experienced and inexperienced at the same time :3
In the end, he's just making it harder on the both of them as their paths collide in the future as opposites. He's forcing a divide that he thinks is best for them both but not realize it's just making things more complicated than it needs to be.
After being chased out of Nightmare's domain, Dream finds himself in Undertop. He's scared and confused. His brother is taller and terrifying while he's still very small. His body is stiff, like he hasn't moved in hundreds of years. Dream may technically be 450 ish years old alongside Nightmare, but it doesn't change the fact that he's still just a kid currently and still needs to grow after being stuck in stone for so many years. He doesn't know where he is or what's going on. All he remembers is the incident that happened before he was turned to stone.
Here in Undertop, Dream is found by Ink and Top. Ink first as he happened to be there when a crowd formed around Dream. Ink's interest was immediately peaked as soon as he laid his eyes on Dream. Ink got up close and personal to check out Dream and all of his fascinating glory. You can imagine how uncomfortable Dream was.
Top ended up stopping Ink and his antics before attempting to get some answers from him. When Dream barely had any, Top offered Dream to stay here with them until Ink could help get them situated. Ink reads through what was left of Dream's script to only find it open-ended. The best piece of information he could get was that Dream's role was the "Guardian of Positivity" which meant he was important in some way to the multiverse itself. Informing Dream of his role as the Protector of all AUs.
Dream, feeling responsible for what happened to Nightmare and the issues he's caused in the multiverse, offers himself to help Ink and his protection of AUs. At first Ink declines mostly because he comments on how young Dream is but Ink is a hypocrite because he's hardly any older than Dream.
Together they grow up, Ink teaching Dream about the multiverse, his responsibilities, along with teaching Dream about his magical abilities that Dream didn't even know they had. Ink becomes one of the only people Dream can go to to just talk and ramble to. Everyone else is still affected by his aura and he's scared of having another scenario like he did with the village. Ink does his best to be a good friend to Dream but there are times he falls flat due to his own situation of attempting to understand feelings. Dream appreciates him regardless.
Over the next 50 ish years Dream works hard to spread positivity through the multiverse to fix his side of the balance. Eventually discovering the Omega Timeline with Ink and forming an alliance relationship with them. There, Dream is offered a home so that he doesn't always have to live in Undertop. Dream accepts but even then he doesn't really sleep there often. Dream has liked the comfortability of an actual house and a bed, but it never felt the same as sleeping under a tree. It was the closest thing he had to remind him of the good times in his former home. So, when Dream has the free time, or is simply tired, he goes off into a random AU just to sleep peacefully in a secluded area under a tree. It gave him more comfort than any luxury could.
Unfortunately for Dream, he hasn't had much time to really pick up hobbies as Nightmare did. He always thought he simply just didn't have the time. The closest thing he had to a hobby was weapon making. He's had several encounters with Nightmare but they were only ever physical fights Dream never wanted to truly participate in. Any attempts of talking, Nightmare would shut it down quick and leave not too ling after. So, mostly to properly defend himself, he began to research weapons. As much as he liked his staff, it didn't give him my versatility outside of shielding. It wasn't the greatest offensive weapon either. And with a little help with Ink, he began to make two more forms for his weapons. Dual blades and a bow. The bow made for long range and for arrows he made out of positivity used to hopefully weaken Nightmare just a bit. The dual blades for close combat if that was ever needed.
These weapon choices allowed him to have different fighting styles for different scenarios. He doesn't want to be feel useless and have Ink do all of the work with Broomie. He actually gets very excited when he sees weapons of interest to him. He loves gushing about the many possibilities he could have with different weapons/fighting styles. ALSO, I like the idea that his weapons are similar to the ones the Huntrix use in Kpop Demon Hunters. The blades made of his positivity and not causing any real damage to the environment around him. He doesn't want to purposely harm anyone either after all.
Outside of the good parts of his life, there's lost of bad. He fear of others getting close to him simply because of his aura is always constant. He has trust issues and can only really confide in Ink, sometimes Top, and only recently Core Frisk (Blue of course is later). He struggles with making any meaningful connections with others who aren't seen as mandatory/important to talk to. And when he realizes he's making a good relationship with someone, he immediately pushes the person away and isolates himself. Dream is a constant state of being lonely and yearning for true connections but also being afraid of them.
It doesn't help that he feels the pressure from others regarding his job. There's always doubts that Dream is doing enough to help the multiverse. There's always others who blame Dream for not being there when Nightmare had attacked their AU and was left to suffer through negative imprint that was left or their AU ended up falling apart due to the drastic damage that wasn't never meant to be there. This is another reason he doesn't fully live in the Omega Timeline. And with all of this stress, he ends up becoming a workaholic to keep himself busy. To make himself feel like he's being useful. Though this also comes with one of my FAVORITE headcanons for Dream, smoker Dreaaaaam. He tries not to do it often, only when he's extremely stressed. Which, spoilers, he's almost always stressed with how things are going and tries to put up a happy face for everyone.
He is only truly happy when he is with Ink and Blue. They're the only ones he truly feels like he has friends and people he can really talk to. Even if he misses when it was Nightmare.
Nightmare and Dream will eventually resolve their issues but that's for years to come <3
