#claywire

I don't think a family tree would help since many aren't related and I haven't drawn every generation of the families mentioned, but here's as quick a rundown as I can give:

BoneLatch and CarbonTheory are sisters (three other sisters were also shown only recently, WashView, AnglePull and GhostFrame), and FateLock is their great grandmother.

Unrelated to that family, HyssopFall is FlickPin's great uncle, and RainBook is FlickPin's very young son.

Unrelated to both those families, PenWell is the one in charge of the building and legal entity that provides housing for CarbonTheory and FlickPin so is frequently seen with both and their friends and relatives - he's like honorary grandpa. PenWell knows FateLock personally they've know each other a long time. He has a brother, ClayWire who has been drawn only once so far. He had more family but they are deceased, only alluded to at present.

PenWell and ReedWalk were best friends, Reed is now deceased

Character!DimeSpin is not related to Pen they are just the same ethnicity (half the same ethnicity)

Because they live in the same house I do intend to depict Flick and Carbon talking in the future - the culture clash 160-year generation gap between Carbon and Pen is just too funny to me so I keep drawing them talking haha

BoneLatch and DimeSpin are best friends

HyssopFall and AtlasKind are best friends

AtlasKind and HyssopFall trained DimeSpin in spellwriting at one point and they occasionally talk

There are older characters I may or may not draw again but they aren't blood related to anyone above. I drew an Atau once who had a fully fuzzy head and neck I might bring her back because it was funny but if I do I have no idea if she knows any of these people.

If Pen hasn't assigned an heir to receive the house Clay could possibly end up responsible for it, which is actually the opposite of what he wants

These multi-family homes have a lot of legal red tape attached to them - a lot of responsibilities and not so many property rights. Pen didn't so much inherit a building as he was put in charge of a kind of non-profit that existed for the benefit of a single large family, and without that family, he's still required to explain where the money goes and why and make an honest effort to continue to serve that role to someone, even if he gets to change the details of who exactly that someone is.

Which works fine for Pen since it was what he was made to believe he was supposed to do for his entire life starting shortly after he became a fully grown adult. Continuing to do the same thing just for different people is easier than trying to find something else to do with his life at this point.

Clay on the other hand wants nothing to do with these burdens. He likes the life he has now, where his responsibilities are just the same ones any adult would have - He'd like to know when Pen passes, because there's an inkling of love there, but also if he stays too easily reachable he could end up embroiled in a complicated probate process one day.