Chara

Chara Masterpost: starryoak.deviantart.com/art/T…
Yes, it was intentional for me to draw Chara with the neutral expression and Frisk smiling. It's just that in life, Chara was only a smiler around Asriel, and no one else. They were slightly dead inside, for the most part. The colors for their sweater when they're a ghost, the yellow on it is thje color of their skin, so I instead used the colors of their sweater from an unused sprite of Chara/Possessed!Frisk (as it was unused, it's unclear which it was meant to be), here the yellow wasn't the same as their skin. I drew The Locket and Real Knife, their signature items in game, and, as I headcanon them as coming from the 1300's, their attire is more old-timey. Their boots are simplistic and peasant like and their sweater is actually made by Toriel, something that they insisted be exactly the same as the sweater they fell in, but ended up being much brighter. Still, it's theirs. I gave them an appearance very similar to Frisk's, as most monsters who knew Chara or what they looked like recognize Frisk as Chara, though they are 9 and 2 years older, they're taller and their haircut is much more straight and clean (copied from their sepiatoned appearances)
Chara was a... well, never really normal child. Of course, that isn't a bad thing... or, at least, had they had the fortune of being born in a different time, their abnormal behavior might have turned out better. As a child, they never really behaved like a child was 'supposed' to behave, quiet and very stilted in their emotions, disinterested in interacting with the other children of the village.... and of course, disrespecting the authority of the Almighty and what He decided they would be. They were disrespecting Him by refusing to behave as their God given gender as female. '
She' was a young girl who would not respect 'her' station as a female, and of course, there were repercussions. But they refused to behave properly or femininely, and they refused to explain why they behaved against the norm, not even behaving as the boys of the village did, even if they were allowed to, which of course they weren't.. Which of course, in today's society would be explained by identifying as not female, but not male, but back then, it was a disrespectful little girl who refused to behave and do 'her' God given duties as a female, nor even attempt the responsibilities of the men in the village, she just didn't belong.
Not only that, but 'her' behavior was abnormal in other ways. 'She' wouldn't play with the other children in the village, nor would 'she' react like was expected from a child. 'She' didn't show emotions and 'she' spoke in a stilted manner.
Over time, the villagers treatment of Chara grew more and more 'disciplinary', and when they neither properly respected the adults nor changed their behavior after the years of attempts to keep them on the path of God, it was assumed that... well, they were not a human. They were assumed to be a Changeling. Now, to be clear, the Changelings of ancient beliefs are not like the creatures seen in MLP.
Changelings in folklore were fairies or demons that replaced normal children with their own fairy or demon offspring, and it is commonly believed now that the real origin of Changelings were simply children who were born with mental or physical deformities; autism, sociopathy, Down's syndrome, or simply children who didn't develop in the expected way or developed at a different rate, and they were often abused in hopes of driving the fairy away from the village.
In this case, Chara was banished from the village and abandoned when they were 9, to return to the demons they came from, or die. Either way, no one particularly cared for what happened to the demon creature that had replaced their normal daughter. In whole, the story of the village really comes down to medieval mental health care sucking horribly. Chara, if they were in today's society, would in fact be recognized as, well, a psychopathic child who does not identify as either gender. Well, technically it would be classified as a conduct disorder before they developed into an adult... but as we know, that never occurred.
After being thrown out of the village, Chara had no place to go, and ran up the mountain in hopes of finding... well, to be honest, a cliff face to jump off of. They weren't interested in living in this world anymore. It was corrupt and the villagers had hurt them for being themselves. Festering hatred was the only emotion they felt about their banishment. They didn't care about any of the villagers, not even their parents. Their parents had been the ones to declare them a demon, to attempt to drive it out of them. They didn't particularly care for the supposed God who condemned them either. But anywhere would be better than the world they had been born in.
Chara's relationship with Asriel was.... complex. Asriel considered Chara his best friend in the world, the best sibling ever, the most fun playmate, the light of his life, but... Chara?... Chara definitely felt more comfortable around Asriel than any other being that they had ever met, they knew Asriel accepted them and everything they did... but they still had trouble feeling particularly good feelings towards anything. Asriel was probably the most important thing in Chara's life... but that wasn't saying much, considering how little they tended to feel about the people around them. Still, if they did enjoy anything, it was definitely playing with Asriel.
While Chara had mixed feelings on everyone around them, they weren't joyless, they just had a different way of expressing themselves. They enjoyed playing with the toys they shared with Asriel very much.
"Chara, what are you doing to my dollies?"
"I'm stabbing Mrs. Pepper for being an unfaithful wife."
"Chara! Mrs. Pepper is... What? No! Don't stab Mrs. Pepper!"
They really enjoyed playing pretend... just not exactly in the way most children did. They used them to tell stories of their village, usually the things they weren't meant to see, and the things that they wished had happened to them... which mostly turned out to involve violence towards the various villagers. Asriel, being the pure, most precious child alive... well, he didn't exactly understand the implications of Chara's actions, and eventually came to the conclusion that they needed to start playing games about stuff that involves stabbing bad guys and not his dollies, since, quote; "Chara likes stabbing my dolls. I guess they want to play games like the guards instead of teatime."... Bless Asriel's little innocent SOUL.
Chara behaved much better around their parents, since they had the wherewithal to know that not every monster was quite as kind and, well, slightly gullible as Asriel. They behaved properly, if still stilted and expression dull, trying to be exactly what Asgore and Toriel would want from them. And Asriel was definitely their favorite, at least because they didn't have someone judging them.