Notice that Xerxes doesn't actually say specifics - he's intentionally not mentioning the Sect, because even though we the audience know he's from the Sect of Strato (I wrote that scene where he reveals his origins to Osric and Ramzi out of the Volume 1 redux), he won't actually tell them until Volume 3.
This page shows a few things: Xerxes doesn't let people push him around; The Sect was so carefree about forbidden magicks (super important plot point for down the road) that even children could transfigure other children into pheasants for example and no one gave a fig; and that Osric is very proud of his non-human bab. Last panel says that even though they're together publicly, Osric still kind of has hangups about people seeing him involved in PDA. Which is okay, that's how he is ;3
And of course we revisit our story-wide theme of revenge, and the drive for justice that kind of anger can give. The only one who doesn't have some long-standing grudge against someone / the world is Ramzi. But that's because he doesn't commit to much of anyone or anything, which is his major flaw.