
... This is super weird for Xavarian, especially right now.
His family would expect that it would be for them.  And it might end up being for them.  But it also might end up being for himself.  He's right on a teetering brink between the family loyalty that was hammered into him despite them keeping him in solitude, and his newfound freedom, and all he's finding that was potentially kept from him.  He doesn't actually find value much in his own person, but instead in what he's after. Anything purposely standing in the way of what he's after is a problem, but if his family goes about achieving it better than he does, then they deserve to be around more than him.  In his mind, anyway.
Due to that, with actual people, it is honestly a tossup and can go either way. Â Insofar as friends, though, he has no one that close to him yet, and certainly not close enough for him to sacrifice himself over.
All that said, Xavarian would sacrifice all of them and himself for Knowledge, hands down.  So that could end up any number of ways.  If he had some knowledge he felt needed preserving, or a strong will to gain a certain sort of knowledge, then he'd fight for himself.  If someone else had knowledge he felt needed preserving, he'd give himself up to keep it intact.  If there were some societal group that held untold amounts of knowledge he felt needed preserving, he'd fight for that.  If more than one of them had knowledge that needed keeping, he'd fight for whichever one logically could hold it best.  ... And this is one part of why he is such a morally skewed character, because what he perceives as relevant knowledge will shift, and likewise, who actually holds it may also shift.  ...He's.. had way too much time to himself to think abstractly.
TLDR: He'd lay it all down for a situational, fluid concept before any current loyalties. Â But in terms of current loyalties, it's a toss up between himself and his family. Â What would make the difference would literally be what the situation was in that moment. Â ... If he thought he had friends, it might be for them, but he'd never fight for the faceless 'Eorzea'.
His family would expect that it would be for them.  And it might end up being for them.  But it also might end up being for himself.  He's right on a teetering brink between the family loyalty that was hammered into him despite them keeping him in solitude, and his newfound freedom, and all he's finding that was potentially kept from him.  He doesn't actually find value much in his own person, but instead in what he's after. Anything purposely standing in the way of what he's after is a problem, but if his family goes about achieving it better than he does, then they deserve to be around more than him.  In his mind, anyway.
Due to that, with actual people, it is honestly a tossup and can go either way. Â Insofar as friends, though, he has no one that close to him yet, and certainly not close enough for him to sacrifice himself over.
All that said, Xavarian would sacrifice all of them and himself for Knowledge, hands down.  So that could end up any number of ways.  If he had some knowledge he felt needed preserving, or a strong will to gain a certain sort of knowledge, then he'd fight for himself.  If someone else had knowledge he felt needed preserving, he'd give himself up to keep it intact.  If there were some societal group that held untold amounts of knowledge he felt needed preserving, he'd fight for that.  If more than one of them had knowledge that needed keeping, he'd fight for whichever one logically could hold it best.  ... And this is one part of why he is such a morally skewed character, because what he perceives as relevant knowledge will shift, and likewise, who actually holds it may also shift.  ...He's.. had way too much time to himself to think abstractly.
TLDR: He'd lay it all down for a situational, fluid concept before any current loyalties. Â But in terms of current loyalties, it's a toss up between himself and his family. Â What would make the difference would literally be what the situation was in that moment. Â ... If he thought he had friends, it might be for them, but he'd never fight for the faceless 'Eorzea'.