So, I gather that in the Better Terms ‘verse, Gil grows up knowing whose son he is? Are he and Agatha raised together? How many people think that they’ve been betrothed to each other since early childhood?

ciiriianan:

Gil and Agatha are raised together in the school aboard the Boys’ airship administrative center.

Gil… grows up knowing he belongs to the Heterodynes, he’s the son of a Heterodyne ally.

Once he finds out which one everyone assumes he and Agatha are betrothed, yeah, – including them, briefly.

Then they decide to get married anyway, and never mind that their father and uncle are being idiots about it.