Brygida was born in Poland; her father was a high-ranking military official who for all intents and purposes had wanted a son. Unfortunately his first child born was a little baby girl, and in the process of giving birth to her, Katarzyna her mother, had complications causing her to never be able to have more children. At first Klaus pretty much ignored Brygida's existence, but when Brygida was 5, he noticed she had a passion for fighting, and was for all intents and purposes, more a tomboy than a girl.
He decided to raise her like the son he didn't have. Unfortunately there wasn't really any room for girls in the military, and at 19 Klaus was determined to marry her off into another high up military family. She was devastated, the last thing she wanted was to be married off, she had dreams, and she wanted to travel. So she decided to run away, while on the run, she ran into some trouble, a rather nasty looking group of men were harassing her. When things started to look really bad, Brygida wouldn't back down was determined to defend herself just like her father had taught her. She managed to take down one of them, but three were still intent on having her. Fortunately for her, Ares was nearby and noticing how brave she was in the face of men, especially for woman in that area and time period, interested him. He went to her rescue, and to make a long story shorter, they ended up having a brief love affair. A couple of months in, she realised she was pregnant, and Ares explained he had to go. Leaving her high and dry and pregnant, she was forced to go home to her family. Not wanting a scandal on his hands, her father arranged the marriage between her and Rafer Kowalski. Rafer was quite a bit older than Brygida, and the only reason he agreed to marry a woman who was pregnant with another man's child was because he himself couldn't have kids, but it was a secret known to very few people. He planned on passing off the child as his own.
Jedrek grew up as normal as any son could with a father obsessed with the military and training, but there was a bright spot in Jedrek's life the day that Marilyn Mazur and her mother moved next door. Marilyn was a year younger than Jedrek, but they became best friends very quickly. By 1912, while the First Balkan War began, they were pretty much inseparable; they even considered themselves boyfriend and girlfriend. It was in 1914 that their lives changed, it was at this time that they were attacked by harpies, found out they were both demigods and pretty much sucked into what would become known as World War I. The war made them grow even closer together, it was clear they were soul mates, but what they didn't realise, was how badly this pairing was driving Ares and Hephaestus insane with anger. It was bad enough they fought over the same goddess, but to have their children in love, infuriated them. What could they possibly do though, Eros claimed the love was destined and refused to interfere, they couldn't do anything to their own children without it breaking the interference rule, and if they did something to the other's kid, it would just lead to war. For months, no matter who Aphrodite was with, whether it was Ares or Hephaestus, they were always griping about Jedrek and Marilyn.
Aphrodite, being her rather typically vain self, was tired of the two always going on about their kids, and decided in order for things to go back to normal, she'd have to step in and do something herself. So in 1916, when Jedrek was 15 and Marilyn was 14, she decided to curse them.
When they are Apart: When they are apart from each other, they do not age, but they are constantly drawn back together, like a hunger that can't be satiated. No one else can fill the void they feel.
When they are Together: When they are finally back together, they slowly feel less in love with the other, and often end up cheating or breaking up. They also age normally when they are together, and when they are literally in the same location, within sight of each other, they do not have any of their demigod powers. They can still fight and use celestial bronze obviously, but as far as powers, they aren't able to use them.
This made Hephaestus and Ares happy, as their children were now miserable, and they didn't have to lift a finger to get involved. For the next nearly 100 years, the two would drift apart and come back together many times. Lately it seems fate has decided it's time for them to be back together, and the two have found each other once again at camp. Because of the time spent apart not ageing, they appear to be roughly 18 at this point.