His mother – the “wife” to whom the Baron sometimes wistfully refers – is the Queen of Skifander, and Zeetha his his sister or half-sister.
When the Baron got time-sealed in Mechanicsburg, one of Gil’s minions addressed him as “Your Royal Highness.”
When the Baron was in the hospital, he warned Gil to watch out for a green-haired woman who might try to kill him.
“Me?! But what did I do?!”
:dubious: “Father . . . what did you do?!”
"Heh-heh . . . I kept you alive!"
We often hear of Skifandrian warrior queens and warrior princesses, but never of kings or princes. My guess is, to maintain the traditional matriarchy, Skifandrian law or custom requires that all royal males be killed at birth. Klaus circumvented that by taking Gil and fleeing the country. After all, nobody knows where he was during all those years when he was absent from Europa.
I think that when Lucrezia drugged him, she sent him to Skifander somehow. Later on, when she hears that he is still on the scene, she says, astonished, “He came back?! Heh…that man.” (Or something like that.) So she thought it would be impossible to return. (This might have something to do with that it is apparently pretty difficult to get to and from Skifander.)
The existence of America, and a few basic facts about it, are known to the inhabitants of Europa, but colonization never happened. So far as I can gather, in this universe, the Native Americans have something comparable to sparks among them (though not necessarily manifesting as “mad scientists”; possibly something more “magical”, and possibly related to the power wielded by the Great Queens of Old), of sufficient power to hold off the combined might of Europa (at least, on their own turf).