"Take a look around you, boy, it's bound to scare you, boy"

He's another of Cass and Medea's half-siblings, and he's one of the three they try to protect the most-- mostly because he's the first one they fully remember being born and attempting to care for.

Middle-aged Hogwarts kid, also does what he can to help his (likely few) friends learn Sign so they can communicate.

He's. . . suspicious of a lot, basically.

That's sort of what happens when your parents start divorcing and ten months later, your little sister is born, and then your dad dies. Not that he really remembers that, because he was less than two, but it impacted him, all right?
He started experiencing hearing problems at around the same time, and by the time he was four, he was classified as Deaf. He had a few years of hearing, so he sort of remembers sounds and how to shape them, but he prefers to communicate in either writing or Sign Language.

He learned ASL at a younger age, so it stuck with him more, even though he's in the UK and had to learn BSL. He has fuzzy memories of the US, and is considered the last of the American generation, but the only sibling he's allowed to help is his full sister Ziva.

The lockdown was really hard on him-- he and Ziva were almost detained as Muggleborns and there wasn't exactly an interpreter, but his dad's family were able to get documents over that Martín Rivers was indeed a wizard, and he and Ziva were able to stay in Hogwarts. He's gotten even more protective of her, especially when two of his older siblings who usually cared for them were sent off to Kolna and Jason stopped responding for a while.

He's got a fairly close relationship with his older three siblings, especially as they spent more time raising him and providing for him than their mother really did.

He only goes by Zachary, never Zac, Zack, or Zach.

Xolo Maridueña (but if you can find another appropriately-aged Latino child actor that would also be great!)