Mayhaps you could explain everything you know about Nightmare, or point me in the direction of someone who has skill?
Well I am not passionate enough about Nightmare to go into detail about anything but my ego is too large to send you elsewhere.
So I’ll call uncorrupted Nightmare Night and corrupted Nightmare Nightmare.
Night is Dream’s twin brother (obviously) who takes on the role as the older brother and wants to protect him. He’s introverted and enjoys reading. Dream gives him books from the villagers to read at the tree, but he’s also protective, caring, confident around Dream, and a little show-offy to Dream specfically as well. He doesn’t know about what happens to Dream in the village anymore than Dream knows about what happens to Night while he’s away, because they’re both trying to save the other the trouble of knowing. They care for each other with their lives and Night knows Dream would never do anything to hurt him.
He’s in no way jealous of Dream. Rather, he takes the apple to try and show the villagers he’s capable of protecting the poositive apples, to prove he isn’t bad. Little did he know, touching the other apple would result in it turning to his own, and that, combined with his negativity, corrupted the entire tree. You see, Nim never told them about this. Nim never tried to warn them. Nim gave them very little info about the tree and their powers beyond the absolute basics. She set Night and Dream up to fail, to both punish mortals for their actions, and show Dream and Night mortals could never be trusted.
Only, turns out the tree was actually being inhabited by another person. Surprise, surprise, it’s who you know as corrupted Nightmare, otherwise known as the mortal who killed Nim. Likely sent by another guardians to kill her, he had a weapon that could murder a guardian, and was so corrupt his spirit got absorbed into the negative side of the tree and was causing all those bonus negative emotions for everyone in the village! :D
He’s now pure evil, purely corrupted by the powers and negativity of the tree, and he sees his opportunity. He uses Night, uses his fear, and the horror of the situation, promises him to keep him safe (which is technically true), and tells him to bite the apple. And he does. With that, he begins consuming the other apples, until there’s no Night left. Corrupted Nightmare has taken full control and Night’s very being is, for all intensive purposes, dead. But hey, the villagers can’t get him.
This is where you get corrupted Nightmare, a horribly corrupt entity that exists as the culmination of all negative energy in the multiverse, thus wanting all negative things to occur, help all negative things to occur, and someone so utterly corrupt with power he only wants to get stronger from there. He has only small parts of Night’s personality and barely any memories of Night’s life, and when he does get flashes of them, he loses his shit and murders everyone in close proximity, or at least gets really fucking pissed. Otherwise, he doesn’t like murdering because it doesn’t benefit his goals to increase negativity. Dream is accidentally turned to stone by his intense hatred toward him (which I think is great synbolism but I can’t go into that right now), and can’t get the positive apple right away. But don’t worry, he can wait. Waiting for the right moment to strike is something he’s very good at.
He’s cunning, crafty, doesn’t kill, never lies (only tells partial truths like the one with Night above), and is an absolute sickening person who would wholeheartedly support anything horrific that could yield negativity (even if he wouldn’t do it himself). In fact, a lot of the time he seems to get other people to do any heavy lifting for him, or at leasts gets others to get their hands dirty. He uses people’s fears, people’s doubts, people’s anxieties, twists them for his own gain. His very presence is so strong that being too close creates huge sensations of negative feelings like anger and panic and fear. His aura is immensely more powerful than Dream’s, and Dream already has trouble with his! The only time he ‘kills’ people is when he gets them to commit suicide from the sheer amounts of horror he puts into their mind.
His goop makes him essentially invunerable to attacks, save for positivity from Dream; he can morph his body and change his shape and size, though it’s based on how much negativity is around him; he’s fast and can move through shadows. I recall him being weak to light, though that could be a misconception I picked up somewhere, so don’t quote me on it. He can’t go to AUs that are too happy or positive, as they prevent his travel there. He needs negative emotions in a place to travel to said place.
I theorize (though it’s probably canon) the only ‘positive’ emotions he can feel are negative positive emotions ie positive emotions from the existence of suffering/pain/negativity, as I know he can’t feel genuine positive emotions like love, but does seem to be content/happy in his horrific actions. He’s only happy in the presence of negativity. He’s ruthless but surprisingly patient, and doesn’t seem to act out of sheer anger if it would get in the way of what he wants. I’d say he’s driven. Extremely manipulative as well, utilizing both his ability to tell half truths, his ability to strike fear into people, and his ability to play off people’s insecurities to achieve whatever he’s trying to. He kills Dream in one of the timelines. Dream kills him in two. So they aren’t messing around and Nightmare is not Dream’s brother anymore. He’s quote: like a zombie. Possessing his form. Making him dead. With only the slightest chance of ever bringing him back. And Dream doesn’t know it.
He’s also trying searching for his original weapon, as well as going after the other guardians, though I don’t want to spoil anything.
There’s a lot more unknowns, especially with the recent reveal Nim may be still be lingering in the back of Nightmare’s mind, as well as his role with the other guardians and past, so I’d say that’s most of what I have gathered for now, though I did generalize some stuff and Nightmare isn’t exactly my ‘specialty’ so to speak. I just know all this from learning about Dream, which means I probably have a higher chance of getting a few things wrong, but I’ll update it if anyone notices something incorrect.
