There's a lot, but this is what I have established for him: He is the only boy and the youngest of the three Nichols siblings. I've been calling him Ri, short for Orion because all three of the siblings were named after constellations. You don't have to stick to Orion, but a constellation name is part of the sibling pattern. Their older sister is Casseopia (Cassie for short). Their dad is super into astronomy and used to take them out camping in the dessert once a year and lug out his beat up old telescope and they'd stay up late eating s'mores and looking at the stars.
They are from Huntington Beach, California. Their parents were incredibly supportive of the kids growing up. Andi went to a different type of summer camp every year, and was sort of all over the map interests-wise growing up. They're all still incredibly close even though their parents are still back in California and they keep in close touch.
Andi loves learning, but she never found just one subject that she loved so she knows a little bit about a lot of things. She turned 27 last christmas, so it would be great if he was 24-26. I'm thinking these two are incredibly close and have a very open and genuine friendship on top of being brother and sister. I would love for them to be best friends, and the kind of siblings who lean on one another and talk frequently. He doesn't have to be as bubbly and outgoing as Andi, but open and engaging with her, at the very least.