House and Dynasty are pretty much interchangeable, here. The only real difference is that House implies a large, interconnected extended family, and the assumption that different Houses interact with or intermarry on a regular basis. The Navigator Houses are a good example of this, they're extremely and intricately interlinked with all the politiking and intrigue that implies. Every Trader Dynasty is technically a House as well, but the only people who 'matter' are the Warrant-Holder and their Heir.<br/><br/>Rogue Traders would be likely to have bastards, just like most noblemen. And if that RT dies without a formal heir, cue the civil war I mentioned among all those bastards fighting for the Warrant. There doesn't<em>have</em>to be an actual wife, but finding one provides the opportunity to strengthen the dynasty with political/economic ties - even without one, it'd be incredibly negligent for a Trader to spend a long period of time without a named heir, even if that has to be a legitimized bastard. So there would have had to been an Heir between Tristan and his father, otherwise he would have gotten more training before now - the best candidate would be one of his elder siblings. And the Heir would have needed to die and pass the Warrant on to Tristan very quickly, otherwise he would have been named the next Heir and started training whether he liked it or not.<br/><br/>The Warp Incursion could have been the incident in question - killing off both his father and eldest/brother sister, but Tristan managing to take command of the<em>Pride</em>and lead it to safety.<br/><br/>EDIT: Now that I think of it, I see Jaded's Tau has the incident where she was recruited involving Chaos Cultists attacking her expeditionary group. That could be the same incident as Tristan's Warp Incursion; demons and Chaos and xenos, oh my.<br/>