Wizarding families tend to band together, and live in clusters as protection against muggles. Half-breeds band together as protection against the discrimination of other wizarding people. That is how two families came to live in a pair of houses merely a few paces apart in rural Belgium: The veela Océane and her wizard husband Cyrille, with their two little daughters Clara and Amandine, and goblin named Bramnok and his pregnant witch bride Émile.
In time, Émile has two sons: the elder Matthias-Gounok and the younger Niels-Zibnok. And Océane had a third daughter: Léa. They raised their children in tandem, and relative peace, blurring the line between family friends and family.
Matthias-Gounok and Clara were childhood sweethearts. Their parents thought it was adorable, and they loved the idea of their kids marrying one another, and were more than a little disappointing that Niels-Zibnok was so platonic with Amandine.
Not a one of them ever thought Matthias-Gounok and Clara wouldn't get married someday, least of all Matthias-Gounok or Clara themselves. But the hearts of children are not always as adults read them to be. Things changed, and change again. And on the day of Matthias-Gounok's wedding, it was not Clara he was marrying but Amandine. Clara was there that day too, of course, and she smiled whole-heartedly, holding hands with the wizard she had invited to the wedding: Quentin.
Matthias-Gounok's brother Niels-Zibnok married a girl named Elise. Léa married no one, and intends to keep it that way. She had been courted by two many boys because she was "the beautiful veela girl," never-mind anything else about her.
Clara and Quentin had a daughter named Hanne. Two years later, Amandine and Elise were pregnant, and their babies were born; first Amandine's Aurélie and then, three months later, Elise's Antoine. And then a few years later, Clara's second daughter, Chloé. Antoine is an only child, but he was raised in the same household as his cousin, and two of her cousins, he doesn't feel like or really think of himself as an only child.
Antoine has white hair, pale skin, and slanted eyes. He has rather goblin-like features and mildly pointed ears. He is short enough that people can see that he's part goblin, but not quite as short as you'd expect.
Antoine's grandfather Bramnok is a goblin, and his grandmother Émile a witch. They had 2 sons, Matthias-Gounok and Niels-Zibnok. The boys were given hyphenated names, one name of each of their races. Lemmens is Émile's surname, as goblins don't have surnames. Niels-Zibnok is married to Elise, and Antoine is their only child. Matthias-Gounok ended up with a veela girl, Amandine, and they have 1 child too: their daughter Aurélie. Antoine and Aurélie both have goblin middle names.
Tante Amandine comes from a family of equestrians, and they kept many horses at their house. Antoine has a horse too, much to his parents disapproval. Théo is not technically his, Théo is technically a shared horses, who belongs to no one in particular, in order to quiet the complains of Antoine's parents, but really he's Antoine's.
He favours his right hand, but can do things with both hands. This semi-ambidexterity is a goblin trait.
He speaks French at home, as they live in south-east Belgium, but speaks Dutch pretty well too. Antoine is also fluent in Gobbledegook because his grandfather, father, and uncle think it's important that Antoine and Aurélie speak the language.