Dark wasn't meant to be an Ego. It was just Mark messing with effects for scary games, to creep out his fans. It was the fans who decided to give 'Darkiplier' life. It was the fans who created him. For a long time, Mark didn't even know of Dark's existence. He didn't know who 'Darkiplier' was, or why his fans were convinced he was an Ego. What even was an Ego? An alter ego, like what superheroes have?
Dark was created before Mark knew about a dimensional plane parallel to the humans', where enough belief could bring things to life. Before he knew that there were bridges in the most public of buildings to get there. Dark didn't know how to leave this plane. Mark didn't know how to enter it, that it even existed.
So, Dark just toyed with his abilities. Tested himself. Saw what he could do against the other figments to exist in his plane; other 'Egos' of random stars. Like his…well, could Mark be called his creator? It was the fans who'd made him, after all. Well, like his 'creator', Dark didn't know of Mark's existence. Who 'Markiplier' was. It gave him a lot of time to think.
Dark found that a chill seemed to follow him. His shadow didn't seem natural; almost alive. With that discovery, came tests. That shadow could knock over small objects, make a screen go to white noise. He couldn't get very far with figuring out his shadow. That is, until Wilford Warfstache came into existence.
The pink-stached 'Ego' was too much for Dark's taste. At first, Wilford was only kept around due to the peculiarity of their features: Exactly the same faces and bodies. But Wilford was colorful, wore a stupid pinstripe coat and had the smell of candy lingering about him. Dark was, well, dark. Gray-skinned, dark-clothed, with an unsettling vibe about him.
The duo was at constant threat of fading. They'd huddle in the corner of a room during the cold nights, breaths fogging from their lips, forms transparent. When the King of the Squirrels came into existence, he'd helped them find warm places to stay, scavenged food for them. Other than that, he wasn't worth their time.
Over time, they grew stronger, forms more solid. They could stand without the risk of collapsing on weak knees; start testing their abilities without exhausting themselves.
When Wilford learned to teleport, that was when the older Ego finally found a good use in him. They started training together, going so far as to test their abilities on each other. They wound up injured more often than not; had been forced to patch up each other's wounds before trying again.
Soon enough, Dark was teleporting and lifting small objects with his strengthening aura.
In time, he became powerful. Confident. With Wilford as his equal.
Then, they discovered Mark through an accident on the human's part. He'd entered their plane by mistake; having followed the King when he somehow found a way out, however brief it was. He became wrapped up in everything they were, whether he liked it or not. Dark was fascinated with the man. That was who they were all…created by?
Dark started making his own appearances on the channel shortly after. It was no longer Mark or his team toying with effects. Unfortunately, there was only so much Darkiplier could do from the Egos' plane. Simple glitches, maybe let his voice be heard. When Mark grew tired of it, he'd give the dark Ego some screen time; taking his team, some recording equipment, and going to the Egos' plane.
And so they discovered popularity gave them power. Dark's abilities grew stronger, more dangerous than they'd ever been. His strange shadow had grown into a true aura that blanketed him, darkened the space around him as if draining the very life and color from a room. The small strings of shadow that could lift an empty mug became powerful tendrils that could throw another figment across a room. A high-pitched ringing started to accompany him and he was changed from the 'goth/emo' he'd been originally seen as into a manipulative, demonic entity.
Then came 'Who Killed Markiplier?' It was just supposed to be a four-part skit. Mark and the team had asked Dark and Wilford to take part in it. Dark reigned in his aura and played the part of Mayor Damien. He'd had no idea that Mark was expanding on canon. He'd thought this would just be the creation of two new Egos: The Mayor, and the Colonel.
Instead, Dark found himself in a puppeted body that was long since dead, broken neck in constant need of being relocated; sharing it with a woman who was supposedly Damien's sister in the stolen body of the Mayor's District Attorney. Dark became truly bitter with their creator after that. That had been too much of a personal change; a low-blow. He was forced to relearn his own body, retest his limits and abilities. He was no longer alone as just Dark. Now, it was Damien and Celine working in harmony with each other to puppet the broken body. Now, the cracks that appeared in his shell were no longer show or irritation with the others' stupidity. They were true fury with their creator, or one of the siblings coming into more prominent control of the body over the other.
There was an upside to that horrid series, however. Dark had never gotten so much attention from the fans because, yes, attention to Damien and Celine went straight to him. He had never felt so powerful. If Mark had been hoping to hinder Darkiplier with the new canon, all he'd truly succeeded in was a pissed off Ego with more power than before.
Dark could teleport. He could manipulate. He had eerily strong control over the UpsideDown now; his aura melting out of it, swirling around him.
Popularity could be a powerful thing.
Like all the Egos, Dark's strength comes from how much attention/popularity he gets from the fans. His abilities include:
-Teleportation: He can travel either on his own or with multiple companions in doing this. If with companions, they are momentarily pulled into the UpsideDown; to them, it may feel like the air has been sucked from their lungs, chilly, and/or that they've gone blind until it spits them back out in Dark's desired destination.
-Aura: Every Figment possesses an aura that they can make visible at will; for most, the auras are just visible light/color used to gain attention and good for not much else. Dark's, however, is also an ability. He can lift/toss/etc. objects or people with it and use it as a means of self-defense. His aura is dark gray (not black), with red and blue lines running throughout to give a 3D effect.
-UpsideDown: Dark has full access to the UpsideDown, which could be seen in 'Who Killed Markiplier?'. He uses this space to scare others into siding with him (often pairing it with manipulation), or to go if the others are really bugging him. It's a quiet place where he can think, after all.
-Reality Warping: Directly linked to his aura and connection with the UpsideDown. He can affect what his chosen victim sees, furthering his attempts to manipulate them by making them see what they want. His aura also appears to drain the color/life from the area immediately surrounding Dark, but will seem untouched as soon as he moves on.
