Christoff Jackson was a regular muggle who worked as a contractor in Durham, England to make a living and supporting his newly married wife, Mary-Ann. The two were a young couple with no thought of the magical world, or of Christoff's ancestry that would play a role in their future. The two had been trying to have children for three years with no luck, going through infertility treatments and trying to figure out why Mary-Ann couldn't get pregnant. The doctors couldn't figure out why her body wasn't accepting a baby, and eventually, the couple decided to adopt, only for Mary-Ann to get pregnant.
9 months later she gave birth to healthy twins, two little boys whom she named Ambrose and Adrian. Ambrose was born 1 minute earlier than Adrian, making him the oldest twin. But unfortunately, after she gave birth to them, the doctors told her she wouldn't be able to have any more children. Mary-Ann and Christoff didn't mind this as much, now that they had their two little bundles of joy to care for and raise.
Adrian and Ambrose were typical muggle children, raised in a middle-class family in England by loving parents and taught everything children needed to know. They were sent off to school, had their one or two friends and personalities and interests like everyone else their age. They grew and developed normally, but the two were really two peas in a pod. They hardly spoke to anyone outside of themselves, save for one or two best friends they had, but even then they always stayed together.
This lasted up until they had their first magical experience, which was an extreme shock to their parents and the boys. Ambrose and Adrian were playing with some kids at their house while their parents were having a party to celebrate Christoff's promotion at work, and the two boys were being bullied by an older kid when they both somehow used their magic to sew the bully's mouth shut and send him flying across the yard. They were scared of what they had done, sending panic throughout the party-goers and their parents.
Thankfully a ministry worker appeared almost immediately to tend to the damage of the kid and obliviate the memories of the party-goers, sending everyone home and taking the time to sit down with the twin's parents to talk about what had happened. Christoff and Mary-Ann were a little hesitant at first, not completely understanding what was going on but if this ministry worker, whatever that meant, was telling them that their children were normal and that this happened more then they thought, then they should at least give them a chance.
Over the next few years the parents, with the help of ministry workers, were able to slowly be introduced into the magical world and their kids had the aid of some private tutors to teach them about magic and Hogwarts and so many other things that were odd and seemed unimaginable. When the boys turned 11 they were sent off to Hogwarts after receiving their letter, thriving within the walls of the magical school and being thrown into a world that they had heard so much about and were finally being able to experience it to it's fullest.
While the boys were away at school, the parents were able to find out through some ancestry work done by a few ministry workers that Christoff was a descendant of the Merlin. It seemed that one of Merlin's offspring married a half-blood, and as the years went on muggles were introduced into the line before it died out and became purely muggle. Christoff didn't know what to think of this but was able to grasp a little bit and understand a piece of what he was being told.
Unfortunately, word had gotten out about his ancestry and a few pure-bloods in the upper class grew furious to learn that the famous Merlin had muggle descendants who soiled his good name and now had children at Hogwarts furthering to soil the magical name. A few radical ones took justice into their own hands, going in the night to the Jackson's home to kill the parents and hopefully the children. The parents were hurt, but an auror or two were able to stop the wizards before anything permanent was done. They were arrested and thrown into Azkaban for the attempted murder of muggles, and the parents were tended to and again had to be told some more things about the wizarding world.
The boys heard about what had happened and grew to hate pure-bloods and some wizards, thinking that they were radical and horrible for trying to kill their parents solely because they were muggles and descendants of Merlin. Somehow this hatred grew between the boys and in 3rd year, they had this horrible bitter rivalry with each other, always fighting and bickering and trying to one-up each other. It only lasted until 5th year where they came back together and grew close again, also opening up an opportunity for Adrian to come out to Ambrose that he was gay.
The two went through Hogwarts smoothly after their 5th year, both of them gaining exceptional grades and graduating with high marks and at the top of their class. They didn't mean to make a statement, but somehow they did with earning high marks as muggle-borns who were thrown into the magical world. They were able to secure some jobs after graduating, with Ambrose going to be a Curse-Breaker for Gringotts and Adrian pursuing his love for spells and magic by becoming a Spell-Weaver.