Newt Scamander disappeared without a trace due to a kidnapping attempt when he was barely 10 years old. His older brother never stopped searching for him.

Several years later there are rumours of a slender young man with an uncanny resemblance to Theseus Scamander, barely more than a teenager who is flying on dragonback (or griffins...) helping people and law enforcement.

+ Newt doesn't remember anything of his childhood but he gets memory flashes around Theseus and perhaps Graves (soulmates?) feeling safe with them.
++ bottom!Newt