Darkness in the Heart

Manehattan was always a busy city. New sights and smells every day. Of course, most of these are bad ones. Ponies enter and exit buildings. Ponies exit and enter the city. This led to pretty much nothing being able to be kept a secret. If it's there somepony will notice it. No exceptions. And no, there won't be an exception in this story.

A random stallion was walking by a street. A busy one, at that, and he was extremely close to the road, but he felt nothing threatening his life, despite the ponies rushing by him. Hay, he could easily die right there, but he didn't, and he didn't feel like anything could kill him.

Anyways, getting that out of the way, he really was just a random stallion; he's so random, we're no even going to give him a name. He was brown with a tan mane and papers as a cutie mark. He was a business pony, with a something new from his job every other day. He was walking when he heard something. It wasn't the sound of construction. In fact, it was quieter than the construction, but he heard it louder for some reason; he knew that the sound was coming from below. But the only thing below him was a sewer. Then he realized it was coming from the sewer on the side of the road. He knew what the sound was: A crying foal. No... two. Two crying foals were trapped in the sewer below him. I need to save them! They're trapped down there, probably hungry and thirsty, waiting for somepony to take care of them. But I can't take care of them, he thought. I guess I'd better save them and bring them to the foster home. Hopefully they'll know what to do with them. He then bent down and lifted the sewer cover and, sure enough, were two foals, crying. They were, for some reason, surrounded by candles, as if somepony was doing a sacrifice. He slowly descended by a ladder and went up to the foals. One was perfectly black, with a black coat and an even darker coat, and the other was perfectly white, with a white coat and a beautiful white mane. But it wasn't the opposite color scheme that confused him; it was what was on the other side of their bodies. They had cutie marks. Bucking cutie marks. No foal EVER had a cutie make at such a young age; they were always a few years old when they got their cutie marks. But, right on their flanks, were cutie marks. What's also strange is that not only their color schemes were opposite, but also their cutie marks were opposite. The white one had a cutie mark of a heart that was also white. The black one had a black, broken heart as his cutie mark. Both were barely visible due to their color schemes. After investigating them, he had to save them, despite them being strange. He picked them up and somehow managed to get back out of the sewer. He kicked the sewer plate back into place and started walking towards the foster home near the suburban part of Manehattan. He walked in, dropped them off, answered the few questions he could, then left. They were the foster home's problems then.

They grew up there. When they grew up, they absolutely despised each other. They seemed like they just wanted to kill each other. They had no birth certificate, but everypony knew they were brother and sister. It was a known fact for some reason; maybe because they were strangely, perfectly opposite. They also grew up with no names. Since everypony thought they were brother and sister, that's what they called each other; the girl was sister, and the boy was brother. The two of them just seemed like average ponies with strange powers.

Anyway, whenever somepony tried to adopt one of them, the one getting adopted would fight back. They would go back to their sibling, with both of the crying. So, they had to be stuck there for a while, because anypony wanting to adopt them would want only one of them. They hated each other, but loved each other at the same time. Over time, it seemed to get stranger. The girl loved her brother, but the brother hated the sister. It was unexplainable. But, after many years, they finally both got adopted; it was an old couple who could not have any foals themselves, so they had to adopt one, or, actually, two. When they got adopted, they recently learned how to read and speak. That was also the time that their powers had became fully available... The powers that they didn't even know they had.