Ah, the Crockers. Curst stepchild family of Haven, or that's the way it's starting to shape up, anyway. For a family whose bloodline is looking more and more important to the underlying structure of Haven, we actually know very little about the Crocker family and how they and their Trouble work (pithy answer: dysfunctionally). But let's give it a try, shall we?
We start with the Crocker Box, which I have to keep reminding myself is not a Crocker Jack Box with a nifty toy surprise inside, and we start with that because the box was commissioned in the colonial era and because it says Crocker on it. We know that the box was originally made most likely by the silversmith Regis Glendower for Fitzwilliam Crocker in post-colonial Haven (1786, which was between the Troubles), and we learn this from amateur historian and genealogist Beverly Keegan (Roots 2x05) with the lead- and followup from Dave Teagues. Apart from that we have no notion of its provenance until Simon Crocker gave it to his son Duke, so that's all we know of its history. As to the nature of the box, we know a little more. The box is actually two boxes, one smaller than the other. The small box says Omnia Vincit Amor on the inside of the lid, which means Love Conquers All, and under a terrarium light the lid says Crocker. In the hinge is a key, which goes to a larger matching box which currently contains weapons, though there's no way of knowing what it contained previous to that. The name on the smaller box, too, is both evidence that the Crocker family was significant in colonial Haven and evidence against it. While certain minerals do have fluorescent properties under ultraviolet light (fluorite being one of those, and very common) it's hard to say what mechanism might have been used to create that name within the box such that it would be invisible to the naked eye. It's also vanishingly unlikely that it would have been visible until artificial ultraviolet light was developed in the last century.
Now, Fitzwilliam is the name of a bastard, and we know this by the 'Fitz' prefix. Fitzwilliam, meaning illegitimate son of William, and Crocker, which might be the mother's name or the mother's husband's name, or the father's name despite the scandal that would have caused. This means several things, first and foremost that the Crockers were likely one of the original families in Haven; this is supported on a meta level by the fact that the Crocker Trouble seems to be one of the most core Troubles in the town, directly affecting other people's Troubles. Only one other person is capable of that as far as we know right now: AudSarLu. So, we can put out there as a working theory that both AudSarLu (whatever her Haven bloodline may be named) and the Crockers are tied in with the origin of the Troubles. Secondly, we can determine that the Glendowers were on friendly or at least civil terms with the Crockers; you wouldn't commission a box with a secret hinge compartment or a secret name emblazoned in the top from just any silversmith. Particularly if you were a bastard in a day when that meant something. The only alternative would be that that Crocker killed the silversmith after it was finished, which is unlikely since the Glendower line is still Troubled (The Tides That Bind 2x07). Thirdly, whatever the boxes originally contained, the Crocker family was keeping one to several (depending on how you count them) secrets from the rest of Haven, and they were very intent on these secrets remaining secret. First the small box which might be easily concealed, and whose owner has also been concealed from casual view, then the larger box with the mechanism to open it removed from the box itself in a more elaborate way than putting a key on someone's belt. That's a lot of redundant backup security for the colonial times. That indicates that the Crockers don't really trust anyone, or at least, they didn't at the time. What they were protecting, well, it might have been the nature of their Trouble, but we don't know that. Yet. Finally, though we don't know the significance, we know that the phrase "Omnia Vincit Amor" is significant. Again, for this, we have to stretch a bit to a meta level, although certainly the main trio have enough information to pull this pattern together by now. We know that AudSarLu has been a significant figure in the cycle of the Troubles in Haven, whether causal or correlated. And we know that whenever she shows up she has a Handler (Howard, the enigmatical bastard) and at least two Significant Friends (Vince and Dave for Sarah, possibly James and Garland for Lucy, and now Nathan and Duke for Audrey). Howard's role seems to be to encourage her to stay and create ties to Haven, but the role of the friends is much less certain. At a guess, the Amor that is supposed to Vincit Omnia is somewhere between these friends, but why that phrase then appears on the Crocker box is yet to be determined.
For as much of a pain in the ass as a pair of boxes is to get information from, surely a living Crocker would be more helpful right? Of course not! Roy Crocker is our next earliest Crocker that we know of, and the first we learn of him is that he was killed by Sarah in some way when Simon was a young boy. We learn this from Simon, who is of course a most reliable narrator, and who then says AudSarLu doesn't have to do it with her own hands, so perhaps Sarah didn't kill Roy directly after all? We get his obituary next, how nicely ominous, learn that he died on August 16 in 1955 at the age of 35, so he was probably born around 1920. For those of you who are curious, the next nearest Trouble peak would be around 1928. Hey, you know who else was 8 when the Troubles first peaked in their lifetime? Nathan and Duke! I'm just saying. The obituary says he also was a long-time fixture of the Haven Shore Club, which for that time and that description probably means he worked as the barkeep for most of his adult life. Over the course of the episode (Sarah 3x09) we learn he was married, had a son, and was distant from both wife and son because of his Trouble and how it was used by a group of people within Haven. Restructuring that information a bit, we now know that in 1955 there was a group of non-Troubled adults who were aware of the Crocker Trouble and used it to coerce the current adult Crocker to kill, and therefore remove a Trouble from the town/the world. From the behavior of the representative of the group in that episode, we also know that these people viewed the Troubled as less than human. We also see evidence that Roy Crocker did not enjoy killing, certainly he didn't enjoy killing unarmed or harmless or defenseless people, so we can eliminate "induced psychosis" from the list of possible side effects of the Crocker Trouble. Roy was killed directly by Sarah in the course of defending herself, while he believed he was defending himself, or possibly in a bout of fatalism. Whatever was going through his mind at the time, Roy sets up the pattern for the Crocker men, perhaps by being the originator or just by being the chronologically first example we have.
Let's briefly digress to the as yet unnamed group that was attempting to pull Roy Crocker's strings, for the moment. Because whether or not they're Troubled, whether or not they're even related to the Crocker bloodline, they are clearly aware of what the Trouble does and have no compunctions about manipulating the Crockers to use them as a weapon against other Troubled families. It's not known how they located Roy, learned of the Crocker Trouble, not much of anything is known except that they physically threatened his family with possibly bloody proof, and that for some reason Roy thinks they can't reach as far as Derry, Maine. Which actually makes them a fairly innocuous group, and doesn't explain why he stayed in town to be manipulated; it seems more likely that the wife and son are in Derry to free them from daily harassment, and as long as Roy remains in town and visible and pliant the group won't take any action against the others. So now we have a group who views the Troubled as less than human, who is willing to do violence to Troubled people in order to eliminate the Troubles, and yet who either shy from or haven't thought of a genocide plan in order to rid the world of the Troubles. Or they have and it won't work, either because Troubles keep popping up or because they're savvy enough to know that some would slip through, plus the Crocker method is more expedient. You only have to kill one person in a Troubled bloodline rather than all of them.
Regardless of why they chose this particular method, it sounds as though this group has remained active at least in some form through the life of Simon Crocker, who followed in his father's footsteps at the behest of whatever group directed him and steered the Reverend Driscoll, upon his arrival, to view the Troubled as cursed. After Roy's death Simon Crocker would have been six years old, and subsequently raised by his mother and whoever else interjected themselves into their lives. We know absolutely nothing about his youth after that point, but we do know that he grew up into an adult who viewed the Troubled as cursed, as needing to be cured, and he is the only example of a Crocker to believe that so violently. Given that we also know he indulged in several self-destructive behaviors and was at best a mediocre parent to his own son, we can safely assume he had problems with self-loathing as a result of this attitude clashing with his own Trouble. It's hard to say when or how he got involved with Reverend Driscoll, but neither of them have demonstrably been in a position to help the other with their various issues, instead collaborating in the downward spiral of anti-Troubled hatred. About the only two positive things we know about Simon, a) is that he somehow managed to be agreeable enough to a woman to get her to marry him and b) there was at least one time when he doubted the righteousness of killing people to end the Troubles. (Which may have been base manipulation of Duke, since we only have his word for why he didn't kill that Troubled person when he had the chance.)
Duke has few fond memories of his father's presence in his life, but he seems to have enjoyed his childhood, even if Nathan didn't. According to the rough timeline we have Simon Crocker died when Duke was eight, at which time we have several things occurring. By Duke's admission, Simon made him promise to come back to Haven if the Troubles came back, though he didn't tell him why. Leaving aside that that's a hell of a heavy promise for a grown man to make an eight year old say, what reasons did Simon have for thinking that Duke would be out of Haven to begin with? Anticipating that his shabby treatment of his wife and son would cause both or just Duke to leave Haven as soon as possible? Anticipating that Duke would want out of this strange, uncomfortable town so badly he'd fly off into the sunset, the way Simon seems to have? Given Duke's behavior (putting tacks into Nathan's back, etc.) he certainly shows signs of emotional trauma. Combined with the information that he won the Cape Rouge in a poker game on his 21st birthday, the fact that Duke had a wife no one in Haven seemed to know about, and Nathan refers to him showing up again over ten years later, it's not unreasonable to assume Simon's guess was correct and Duke got the hell out of Haven as soon as he could. Other things we know are that he doesn't remember what happened the day the Colorado Kid disappeared, though he has other very clear memories of things that happened around that time/when he was that age. We know that he had a babysitter but we have no reference to a guardian or caretaker, so it's not unreasonable to assume that he was under the care of his mother. And finally and most importantly, we know that Duke did not know he was or would at some point be Troubled, nor what the nature of his Trouble is.
Let's get back to that, then, and the promise Simon made Duke swear to. Simon grew up without a father from the age of six, which isn't the automatic psychic death sentence that many focus and social groups would have you believe. But when your father is the only link to or explanation of what is happening to you when your Trouble kicks in, that becomes a great deal more significant. We have no information about either of the Crocker wives, so we don't know if either of them knew about the Crocker Trouble. Given that Simon later grew up to be an assassin working with the Rev's group of Troubled-haters, either Simon's mother sided with the Troubled-haters (unlikely, since they were threatening her and her family's lives, unless again she didn't know anything about that) or she didn't know and couldn't tell him. This leaves Simon to tell Duke about the Crocker Trouble, which he very obviously didn't. He didn't tell Duke about that, he didn't tell him about what he himself was doing, and he didn't tell him any specifics about the group he was working with. Taking all of this into consideration, my current conclusion (which is somewhat different from my initial conclusion of Simon is a jackass who needs punched) is that no matter what Simon thought about the rightness of what he was doing, he wanted Duke to make his own choice based on what Haven was at the time. He made Duke promise to come back to Haven if the Troubles ever returned, most likely so that Duke would have his own experiences with the Troubles, but all Duke knew was that his father was involved in dangerous, secret things. Simon left it up to Duke, whether as a conscious choice or unconscious rebellion against the group that may have controlled him, to come to his own conclusions about what the Troubles were and what he should do about them.
Which isn't to say that Simon was a good father. He did that one thing right, arguably, but he still put Duke in the position of having to be a parent to his parent, which is a shitty thing to do. Duke has memories of bandaging up his father, buying him beer or smokes, sitting back and watching his father express self-loathing and hatred of what he is and the things he's doing in so many of the worst ways possible, which led to Duke having not much of a childhood. Which is why it should be largely unsurprising that Duke got the hell out of Haven when he had the chance, and most likely why Duke's characterization in the first season and a half of the show is that of an overgrown manchild. His behavior is minimally responsible, though he does have some very important and significant moments of taking responsibility and meeting expectations/dealing with the consequences of his actions (the Grey Gull, the child with Helena despite that he'll never meet her). He treats Nathan with what I think I can best described as friendly contempt, showing no respect for Nathan's profession or most of his choices but also showing no personal animosity towards Nathan, specifically. He treats Audrey similarly, but with a more blatant element of flirtation since she doesn't have the history with him that Nathan does. But, through the first season and in more detail through the second, he begins to realize that whether he wants to or not, he is in the middle of something serious that requires him to treat it with gravity and respect. This process begins with him finding out about the circumstances of his death and the involvement of a man with a tattoo on his arm, and most recently has involved him discovering more about his family and how others view and treat the Crockers.
Duke is a different kind of Crocker than his father and grandfather. Despite now knowing at least most of the nature of his Trouble and how important it is to many people in Haven, he chooses to accept only the basic biological (as much as biology has any place in Haven) facts about his Trouble and not what anyone else thinks he should be doing, up to and including Audrey. When learning new facts about his family history such as the fact that AudSarLu has killed both his father and his grandfather, he chooses not to treat Audrey Parker as though she performed the acts herself. When he is in a position to address Sarah's killing of Roy Crocker directly, his solution is to ask both of them to choose not to kill each other. And it might even have worked if Roy hadn't continued to attempt to kill Sarah, leading her to defend herself with fatal results. It's worth noting here, while we're discussing that, that Simon mentioned Audrey doesn't have to kill Duke with her own hands. We don't know if that's because Duke corrected his father about the prediction that Audrey would kill him (as per Vanessa Stanley's vision, he assumes a tattooed man is supposed to kill him) or because Lucy didn't actually kill Simon Crocker, he only assumes she was involved in it. There are, apparently, many candidates for Simon Crocker's murder; even Simon himself believed Garland Wuornos was in on it. The past two generations nonwithstanding, though, Duke is spending most of the third season focusing on the choices he makes with the information about his family history available to him, and trying to hold onto the belief that making different choices will change the Crocker male life arc: Lose father at a young age, grow up to kill Troubled people and end that Trouble forever, die around age 35 at the hands of AudSarLu's current incarnation. In a way, and going back to the saying on the box of Omnia Vincit Amor, this Crocker arc might be a sign that things have gone very wrong in Haven and far from what the Troubles were originally intended to be. It might be that Duke's choice to trust in Audrey and his love for her rather than choose how his father and grandfather did is what saves him and helps to change Haven's cycles. However, that also assumes that the Troubles were originally intended to be anything, and that Duke's choices make a difference. The message of this season seems to run strongly counter to that.
As last season was about the discovery of his heritage, this season seems to be about choices. Duke's choices to share the information he gets contrast sharply with Nathan's choices to keep his mouth shut about almost everything. Last season we discovered the Crocker boxes through a series of increasingly unlikely coincidences (A: Hey, it's that thing we don't believe in!), starting with Howard writing the coordinates in a book he leaves for Audrey, through to Duke being the one to accompany Audrey II to Kick 'Em Jenny Neck rather than Audrey herself. This leads to Duke finding the map, the coordinates, digging a hole because something has to be down there that's connected to all the mystery, finding the board that says "Town of Hayven, Rasmussen House" (and who is Rasmussen and how does that name connect with the Crockers? We have no idea! Isn't it great?), which creates an arrow which leads to the first box. And then the first box leads to the second box. Now, either Simon or someone close to him went to all that trouble of setting up that Rube Goldberg Scavenger Hunt to hide the box with the key to the second box from Duke (and if so, fucking why??) or Simon had a spare key and the smaller box was initially hidden longer ago. Simon Crocker's psychology doesn't seem to incline him to Rube Goldberg Scavenger Hunts, so my best guess is that Simon had a separate key, or that Duke was supposed to force or pick the lock. But when we find all of this including Simon's journal in the larger box, Duke immediately shares it with Audrey. Not only because she's there to see the open box, we later see them sitting down reading Simon's journal together. Duke chooses to put his trust in her and, less immediately but no less thoroughly, in Nathan. This doesn't seem to be working out any better for him than the keeping secrets would, but it's not over yet and it's making him some powerful allies, particularly with Audrey, who clearly cares for him and values their friendship.
And again, these choices may be what brings Duke Crocker and his Trouble around to participating in the salvation of Haven, whether that means stopping the Troubles or creating a more benevolent way to live with them. The Crocker function in the town up until now seems to have been one of last-ditch desperation for the cure at best, or the brutal annihilation of the Troubles vis a vis Simon Crocker and the Rev's fire and brimstone philosophy. There is thus far no evidence that the Crocker Trouble causes that kind of bloodthirsty murder-seeking psychosis, anyway. It might be that the Crocker Trouble was originally only designed as a blood test of who's Troubled and who isn't, as Duke was seen using it recently, and then as a last-ditch way to get rid of Troubles that can't be contained by AudSarLu's assistance. We really have no idea, and what we know of the Crocker bloodline is patchy at best. For that matter, what we know of his supposed killer is equally patchy. The last thing you see before you die could, after all, be a helping hand. With Nathan having a tattoo now, there's even a chance it would be, setting aside the unprintable Glendowers who we hope to hell are staying out to sea. And we have reason to hope that Duke is being set up to break the pattern; among other things he doesn't appear to have a young son. (Though given what a surprise Evi was, we're not calling it either way just yet.) More strongly in his favor, he's making allies and refusing to let his family's secrets bind him.