[@semicolon] I could see them knowing about each other at the very least. It's possible that the Ciervos were kind of cleaning up a mess around their borders, and maybe Fis' family caught sight of them sealing up a demon or something, so the two families kind of traded tips over that? The Ciervos probably didn't/don't approve of the constant summoning and binding of demons, as they view it as a bad omen, but as long as Fis' family didn't act in an actively hostile manner towards them or defile their gravesites I think they'd treat the Kalix family fairly amiably.