Bastian Horus Nimr was born on August 29 in Cairo, Egypt to Abasi and Chione Nimr. He was the last of their children, making him the baby, and he was treated as such. Not by his parents, however, but by his siblings and nannies. His parents were always away for work purposes, leaving him and his siblings behind at their home. Throughout his childhood, Bast never really desired anything. Because his family was wealthy, he never went without food, clothing, or toys, and his siblings gave him all the love he needed to suffice. Really, he had a happy childhood in his opinion even though his parents weren't really in it.
His first sign of magic came when he was 7. One of Bast's sisters (most likely Cleo) had gotten a cookie from the jar and instead of getting one for Montu or sharing, she stuck the jar up on the highest shelf so Montu couldn't reach. This had caused Montu to go into a fit of rage, and Bastian hated when his siblings fought. Even at that young age, he was still considered the peace-maker of the family. In a matter of seconds, Bast had caused the cookie jar to come crashing down on the kitchen floor. He proceeded to hand his brother a cookie and clean up the mess. Of course he got fussed at for breaking the dish, but again, it wasn't by his parents, but rather a maid or nanny.
When Bast was of age, he went off to Uagadou, just like his older siblings. He was thrilled to be going off to school with his sisters and brother. In all honesty, he'd gotten very lonely when they had all left him to attend the school of magic. At Uagadou, Bastian thrived, making friends and developing his personality and character. In his fourth year, Bastian realized he was crushing on a boy named Taavetti. It was then when he determined his sexual orientation. Although he hoped his family wouldn't mind which sex he preferred, he was still terrified to tell them.
After his final year at school, Bastian decided to come out to his family. He had never been so happy to get something off his chest. But that happiness only lasted a few seconds before his parents disowned him in disgust. With nowhere else to turn to, his older sister Tris happily welcomed him to live with her. Bast was more than content to live with his sister. Out of all his siblings, he happened to get along with her the best. Not to mention, she never shamed him for who he was.
Right before Tris was to be made Head Auror, she had an accident in which she fell into a coma for six whole months. In that time, Bastian picked up a couple of jobs that would pay the bills and take care of any medical expenses. When his sister finally awoke, the healers demanded she be sent to London for rehabilitation. Bastian was more than on board with this decision. He'd go anywhere as long as it meant his sister could get the medical treatment she needed.
In moving to London, Bastian also had better opportunity to pursue his dream of being a famous actor. It was there where he landed his first gig as an extra in an insignificant TV show. That was more than enough to encourage him to continue with his dream. He had a couple more minor successes, but nothing too major. The best thing he has gotten so far is an interview with one of the most famous Wizarding World TV Networks - he's banking on a job with that company. Hopefully all his hard work will have paid off.