In my theory I always thought she was from the human world it always made sense to me that she was

Personally, I like the idea of Tirek, Chrysalis and Cozy Glow being an Evil Family.

probably a self-made orphan, knowing that pony.

@Bunny-CarrotHunter  
She’s more of an OC from baby’s first fanfiction than a believable character in the world of Friendship is Magic. That’s not to say you can’t have a deceptive cute/kid antagonist. Betty from Glitchtale is essentially Cozy Glow done right. At first, we see her as a cute cheerful girl who befriends Frisk, but then we slowly learn about her plan and motivations, and everything takes a darker turn, she even manipulates Glitchtale’s equivalent of Chancellor Neighsay and sows mistrust between humans and monsters, all the while being threatening. And we actually got to learn about her origins as well as her powers, which makes her actions throughout the series all the more believable.
 
All in all, Cozy Glow is a shit character created by shit writers.

@Background Pony #545B  
You really don’t like Cozy, do you?

@Bunny-CarrotHunter  
It’s likely she was written without any backstory in mind. She’s based off of Darla Dimple and the staff wanted to have a character similar to her. The difference being that Darla Dimple makes sense as an antagonist in both the story and setting Cats Don’t Dance establishes, whereas Cozy Glow being a major antagonist in Friendship is Magic feels woefully out of place.
 
She’d work better as a minor antagonist like Iron Will, and the Flim Flam Brothers, because they were comical and didn’t pose much of a threat, but when you have a major villain that goes cartoonishly off-model and acts over the top even for the show’s standards it breaks the viewer’s suspension of disbelief because the show establishes the kinds of characters the major villains are and the threat they pose. It’s like making the Fire lord from Avatar act like Plankton from Spongebob. It flies in the face of the setting. Yes, MLPFIM is cartoonish, but at least in the first few seasons, it knows when to get serious and drop the cartoonish shit. That’s why Cozy Glow fails as a character, and by extension the staff fail as creatives.
 
 

 
Let’s not be coy, if that had happened, Haber wouldn’t have gotten a smug sense of satisfaction from ripping a page out of Rian Johnson’ book on subverting expectations.

I think it was kinda obvious she was an orphan (or just VERY neglected) because of how free she is to roam, be send to hell, stoned and hang around ancient villains. I still would of liked if they mentioned something about her backstory in the finale, even if something brief like “Hey, could be worst. At least you weren’t abandon by your parents on the doorstep of the nearest orphanage, right?”  
Obviously not that dark/blunt, but something like that.  
Also one of the reasons I kinda wanted the Mean 3 to end in a little found family like trio/trope.

I wonder if she’ll get any backstory in the IDW season 10 comics. Even if she was born evil, (which it’s really impossible to say given the limited information about her,) we don’t know anything about why she wanted power so badly, or why she was so skilled at planning and manipulation. I’m not saying the writers should provide us with every single detail about her mind and life, it’s great to have room for speculation, of course, but it’d be nice to have more than nothing to work with.

“…hella abusive parents”
 
Looks like somepony is from Northern California

My headcanon is that whatever happened to her parents, she’s the one who did it.
 
(Either that or they’re just scared of her.)

@Zenitheus  
I know that. But all the same, until we get some more canon origins for these guys, I’m just gonna go ahead and count Tirek’s origin comic as canon.

@ThomasFan45  
Those were comics, not the show proper. I’m not asking the writers to include details from those stories, but at least have the characters give us hints or retell stories about what happened in their pasts.

@Zenitheus  
We may in the upcoming episodes, though.
 
Even then, Tirek and Chrysalis got a little backstory in the comics (even if Chrysalis’ did kinda suck).

@Background Pony #302B  
Seeing that we don’t learn a shred of Tirek, Chrysalis or Cozy’s backstories in season 9, even during the campfire scene in Frenemies that seems very unlikely.

I hope in the last season finale they reveal Cozy Glows backstory a little. A wanna know what happened to her and why she’s so evil.

@Background Pony #0D98  
👍

@ThomasFan45  
Agree.

@Background Pony #C3EF  
Yeah. A lot of people thought she was evil long before she met the CMC. I just figured, if that was the case, why did she still try to help them out when they got banned from the school?
 
Therefore, Cozy’s descent into villainy had to have happened in the time between ‘Marks For Effort’ and ‘School Raze’, when she was learning about the power of Friendship Magic at the school.

@ThomasFan45  
I thought the same.  
She seemed more normal (with some power ambitions maybe, as seen in the montage when she was learning the elements) but still normal, but then it all went to her head once she noticed how powerful friendship is.

@Background Pony #0D98  
Thanks. I may flesh this theory out more on my own account one day.

@Background Pony #0D98  
she did act very well with the CMC. she also has a rook for a cutie mark.

@ThomasFan45  
Wow, that is a good theory, too. Twilight’s school has bad influence.

@Background Pony #D052  
Yes, I also wondered is she really a child, or just acting it.

@Neko Majin C  
Personally, I think she was a normal filly until she got into the school. There, she learned about all of the Mane 6’s adventures and how friendship is powerful enough to take down any opponent (ex: Nightmare Moon, Discord, Tirek, etc). That’s when she got it into her head that friendship is power and that’s when she started to form her plan.