The Luminaries is truly the sum of many parts/stories/characters, and Walter Moody is at the heart of it…and yet, at the same time, totally secondary.
Wait, how can that be? Well, the thing is, old Walt is the first person we meet in Hokitika, and it's his story that leads us into the behemoth tale of intertwined conspiracies, mysteries, and violence that actually sucks up most of the air in the book.
Despite all that, he's pretty peripheral to this web of lies and conspiracies—as the saying goes, not his circus, not his monkeys. But yet, he does help untangle those mysteries and assist characters in getting out of the trouble these mysteries caused…See, now do you get why he's both central and not?
So, yeah, he's the protagonist, even if he doesn't necessarily get the airtime your typical protagonist would get (case in point: his storyline ends about 100 pages before the novel does). Here's what you need to know about him.
Planets and astrology are pretty important to the novel's structure, and each of the major characters is associated with a planet or zodiac sign. Walter is associated with Mercury, which is the "planet of communication."
It makes sense that Catton would associate Moody with the chattiest planet, since Walter certainly thinks a lot about how to talk to people—and get them to talk to him.
For example, when he arrives in the smoking room of the Crown Hotel and realizes he's interrupted some kind of covert meeting, he thinks carefully about the best way to earn their trust and thereby become privy to their secrets. His approach is to share some personal deets regarding his own family drama in the hopes that it will draw them out:
Walter Moody was much experienced in the art of confidences. He knew that by confessing, one earned the subtle right to become confessor to the other, in his turn. A secret deserves a secret, and a tale deserves a tale; the gentle expectation of a response in kind was a pressure he knew how to apply. (I.1.131)
His trick works, of course, and soon he gets waaaay more confidences than he bargained for, as the twelve men tell him about a series of strange and seemingly interrelated happenings that they've come to the Crown that night to get to the bottom of by pooling their collective knowledge and reflections. Although Catton (mercifully) arranges their barrage of voices into a coherent narrative, it must have been quite a mess in the telling.
When it's all out on the table, Moody's twelve new friends want to know what he makes of it all, and Moody realizes that he now has to play kind of an important role in helping them untangle the mysteries at hand:
So I am to be the unraveler, Moody thought. The detective: that is the role I am to play. (I.12.41)
And that sure does end up being his role. In fact, since he's a lawyer, he ends up helping Anna Wetherell and Emery Staines get out of the legal troubles they end up in because of these mysteries…
Moody's importance as the novel's big storyteller/"unraveler" figure can't really be understated—and Catton herself draws a lot of attention to it. When we last seem him, in fact, he's about to tell his new friend Paddy Ryan his story to pass the time while he's traveling. Very clever, Catton, very clever.
Why is this so important? Well, bear with us a second while we get a little philosophical here:
With all of its emphasis on the zodiac and planetary shifts, the book is playing with the tension between destiny and chance—or, put differently, determination and freedom.
If the twelve characters in the Crown's smoking room at the beginning represent fixed astrological "points" that interact with the planets in a predetermined, cyclical way, storytelling is a way of arranging and making sense of all those facts, events, etc. in a way that can actually change the future. Lydia Wells's theory of fortune-telling actually sums up this function of storytelling pretty nicely:
… nothing about the future is incontrovertible…the reason is very simple: a person's fortune always changes in the telling of it. (II.10.51)
So, to really oversimplify: talking about stuff changes things. Deep, right?
Catton really drives home storytelling's power in this regard when she (repeatedly) draws attention to how characters, if they had just heard X or Y in time, would have done things differently. So communication is really, really powerful in this book, which makes Walter Moody (as Mr. Communication) pretty powerful, too.
According to the table of contents, Moody's "related influence" is "Reason," which seems appropriate, given that he's a lawyer—we would hope he's able to argue/think rationally. He certainly prefers to make decisions based on what he sees/can be analyzed rather than taking flights of faith.
We learn this when he's chatting with Lydia Wells about her upcoming séance, and she's trying to bait him into saying he thinks it's a bunch of hooey (which he does). Reflecting on what it means to know something, he says, "I suppose that to know a thing is to see it from all sides" (II.10.244-245). Which of course, as Lydia Wells argues, doesn't work when you're talking about intangible things like "spirits, "which she believes you can know.
Walter says he disagrees with that, but we know from his discussions with others that this isn't strictly true: he is pretty well convinced that he saw Emery Staines's ghost while he was aboard the Godspeed. In fact, he had remarked that that theory was semi-confirmed just that morning when no bloody body matching the person he saw was discovered in the wreckage of that ship.
So, one funny thing about the book is that there aren't a lot of women in it, but we do tend to get a lot of detail about how the male characters feel about women. In Moody's case, despite pretending to be on the same page when his friends talk about women and sex, he's actually pretty innocent:
To put it plainly, Moody had never taken a lover, and did not know a great deal about women, save for how to address them properly, and how to dote upon them as a nephew and as a son. (II.4.60)
He pretends to be all worldly in that regard, but apparently he's anything but.
Although we've already given you some of the more important aspects of Moody's character—you know, like his potential to change human destiny—we would be remiss if we didn't mention the fact that he's (according to Catton) a total fox:
Moody was not unaware of the advantage his inscrutable grace afforded him. Like most excessively beautiful persons, he had studied his own reflection minutely and, in a way, knew himself from the outside best; he was always in some chamber of his mind perceiving himself from the exterior. He had passed a great many hours in the alcove of his private dressing room, where the mirror tripled his image into profile, half-profile, and square: Van Dyck's Charles, though a good deal more striking. It was a private practice, and one he would likely have denied—for how roundly self-examination is condemned, by the moral prophets of our age! (I.1.4).
So, yeah, there you have it—Walter is good looking and chatty and, unlike most of the other men in the book, doesn't have an extensive knowledge of prostitutes. In other words—he's a total catch.