Prevention and Pursuit
"Still, someone has to find out who did this, track them down, and stop them."
Poplock hopped on his head and then leaned perilously over, looking down into Tobimar's eyes. "That's an awfully tall order for one exiled Prince and a somewhat height deficient Toad."
-- Tobimar Silverun and Poplock Duckweed, Phoenix Rising
One of the most challenging parts of law enforcement in a high magic world is the sheer variety of powers available to would-be criminals. Here, if we have a vault with solid walls and a locked door that is somehow emptied, we know that the thief had to come through the door (since the walls would otherwise have holes in them), or used some very mundane means to get someone to bring the stolen goods out in some apparently legitimate fashion.
On Zarathan, on the other hand, the thief might have walked through the walls using magical, divine, or psionic abilities; might have used a clairvoyant spell to divine the precise location of the goods and some other spell to summon the loot to him; might have mind-controlled the owner of the bank to remove the loot himself and then erased the memory so that the owner honestly has no knowledge of the crime; the loot might never have been there and it was all an illusion; or the crook was a shapeshifter and convinced people he was the owner; and so on.
Of course, there are similar varieties of protections; there are anti-teleportation and "phasing" enchantments (Poplock mentions some of these in passing), wards to prevent passage or suppress scrying, and so on. Moreover, the enforcers of the law have equally diverse tools for their investigations.
The other challenge law enforcement can face is bringing the criminal to justice. In our world, if you figure out who the crook is and where he is, it's generally straightforward to bring him in; yeah, he may be armed, but there's a vanishingly small number of perps who will be better armed than the police, and essentially none that could directly take on multiple SWAT teams. This is very different in some magical worlds, even those which at first glance appear relatively low powered; for instance, while he rarely uses his full power, Gandalf the Grey in The Lord of the Rings is immensely more powerful than almost everything he meets, only the Balrog, Sauruman, and the Witch-King having equality or near equality with him (Sauron he never directly meets); if he chose not to be taken prisoner, there's virtually nothing in that world that could take him in. Similar things are at least arguably true in other fantasy worlds such as Brooks' Shannara, Barbara Hambly's Darwath series, and so on.
This is doubly true for Zarathan. Only in superhero worlds (which have their own set of different assumptions and tropes) is there a greater potential disparity between the power of the individuals committing a crime and those tasked with bringing him, her, or it in. A normal person on Zarathan – one of the average citizenry – is little more powerful than an average person on our own world. They may know some minor magic which serves them in the same capacity as, say, vacuum cleaners and clothes washers here, but in general they're not much different from us.
By contrast, a powerful wizard, psionic, servant of evil (or even just amoral) gods, or even a highly-trained warrior on Zarathan can be vastly more powerful than the rank-and-file. Most highly capable adventurers (I use the lowercase to include the good, the bad, and the ugly as well as the "Adventurers" who are guilded, self-policed independent troubleshooters, in a sense) are not the sort to join local law enforcement, and while of course any major city or country will have its own high-powered agents, there's a hell of a lot more high-powered people out there who are not part of the enforcement organization.
How powerful? Well, on other worlds this can vary, but one can take a look at the battle between Kyri and Thornfalcon and get a hint. These are people demonstrating superhuman strength, speed, and endurance, wielding powers far beyond normal human capabilities; Thornfalcon can send lightning rampaging through an entire (quite large) clearing, striking everything but him in the process, while Kyri can call upon her god and release a blast of purifying flame that eradicates hundreds of monstrous creatures AND shatters a dimensional portal.
Admittedly that last is a sort of special case… but not that special. As of yet, Kyri hasn't even gotten close to the beings who are really running the show. The top end of what one may have to deal with on Zarathan is mentioned in passing by Tobimar and Xavier when Xavier is told that a small (relatively speaking) set of mountains was created when a single combatant fell on the road. (While it's not made absolutely clear in the novel, this story is in fact literally true; it was one of the Greatest Dragons, back at the time of the Fall of Atlantaea.)
So how, exactly, can your investigative team bring in Magalath the Shadow, a master of both summoning and symbolic magic who's been known to control elementals capable of leveling (or raising) small mountains?
The simplest way is of course the Big Hammer approach – call on one of the Gods to help you grab him, or get the most powerful mage on-call to help. But the gods have their own rules and counterbalances, and they generally aren't keen on directly intervening in mortal affairs (often for political/strategic reasons); it's also not at all unusual for another, opposing god to counter the actions of the first, so you can't really rely on deific help in many mortal settings; for a deity to be willing to directly contest through another's opposition requires something very important to that god, as it's possible they may be triggering direct hostilities on their own level by doing so.
Of course, the equivalent of the police "staff mage" is likely to be an investigative, not combat specialist. Even if he or she (or it) is highly experienced, many of them won't be really expert in fighting prepared magical adversaries, any more than CSI techs are really prepared to deal with paramilitary forces in the field. So that leaves two possibilities: bring in the equivalent of government help – "special forces", so to speak – or go for freelance operatives.
In the State of the Dragon King, the "Adjudicators" are the closest to the government special forces you'd have. Some of these are indeed extremely powerful and competent – Toron, for instance, is more than capable of dealing with most opponents of almost any type – but there are not many of them, and their primary function is actually more as a major part of the police force and judiciary combined. That particular country doesn't really have much of a standing army as such, but instead has a large range of smaller private forces which can be called up at need.
This is where the "freelance operatives", usually called "Adventurers", come in. The Guild Adventurer is an independent agent who may use many different techniques to achieve their goals, but who adheres to a certain set of basic codes as laid out by the Guild. The code isn't terribly long, and most of it boils down to "By all means improve your situation in life, but do it in a way that helps people. Respond to calls for assistance and do your best. And make sure you don't embarrass the Guild." As the Guild is, by its nature, composed of a large proportion of the most powerful individuals on Zarathan, even someone near the top of the charts in terms of power would think long and hard before trying to screw the Guild over.
I mentioned superhero universes earlier, and in many ways this parallels such universes. In both cases you have a proportionately small number of individuals which happen to wield staggering amounts of power, some of them benevolent, some of them malevolent, and really the only things that can reliably stop the malevolent ones are members of the benevolent group of high-powered beings. In both there are legitimate, well-trained people who are overall in control of the political and social operation of the world, but who are specifically powerless, or at least weak, against these types of individuals, and so rely on the benevolent members to assist them in maintaining safety and order.
It's important to emphasize that on Zarathan, a "country" is very little like a "country" here on Earth. This is described to Xavier in some detail but it bears repeating here. When we look at the United States – or even just one of the states, such as New York where I make my home – our maps indicate that ALL of that territory is part of the state or country. Moreover, this is pretty much true; while there are certainly wild areas of the state and places where there are few people, there's really nowhere that you could point to and say that New York's government, and through it the United States' government, doesn't control it.
This is the opposite of Zarathan. While the map accompanying Phoenix Rising (and ones used by people in the novel) shows great swaths of territory claimed by the State of the Dragon King, the Empire of the Mountain, and so on, in actuality these great countries are just a few cities and the territory around them and the Great Roads. The repetition of the Chaoswars, the multiple intelligent (and often hostile) creatures in the various wilderness areas, and the powers of gods and magic which are not always under control make most of the continent a constantly-renewed wilderness, filled with the ruins of possibly hundreds of prior civilizations of various ages and power levels (there have been 40 or so Chaoswars, with as Khoros states an average interval of about 12,000 years or about as long as any civilization has existed on Earth; it is therefore quite possible for there to be many separate civilizations seen in the course of any single period between Chaoswars. Thus, threats ranging from a hostile pack of wolves or giant spiders to a reawakened god can emerge from these places without warning.
Besides meaning that the idea of a safe and quiet country is limited to the large cities, it also implies that there is a huge region of no-man's (or any other beings') land which criminals and worse can escape to without being really within the grasp of the normal police or guards of the cities.
Adventurers are the immune system of this fragile body of civilization. Sure, many of them are strongly motivated by money and glory, but most of them are also genuinely interested in helping the less fortunate. True, a large number of those probably do so out of somewhat cynical motives, but hardly all of them, and it's what they do and say that really counts. They're the ones that go out where it's too dangerous and find out just how dangerous it really is; they're the ones the police or guards call upon to chase down that previously-mentioned miscreant, Magalath, and bring him to justice; it's the Adventurers who find themselves in the front of the line when their homes are threatened by invasion.
Of course, it's sometimes also the Adventurers that let the demon out of its sealed crypt, but hey, no one's perfect.
The police or guards of a city who are faced with a potential opponent of superior capabilities, therefore, will often inquire after available Adventurers of an appropriate level of experience and skill to assist them. This may include basic investigation, or range up to and including direct combat and even authorized execution if necessary. This is of course how Tobimar and Poplock got brought into the search for the "false" Phoenix Saint.
Much of an Adventurer's work is in assessing the situation and determining if it's something they can handle; many of them will of course be risk-takers and overestimate their abilities, but those who survive to any reasonable level of skill and power generally have a good handle on their own capabilities, and experience in judging their would-be opponents.
This is the choice that Tobimar and Poplock face when hired to (as they believe at the time) hunt down a false Justiciar. It's fairly clear in the text that if they didn't have other, external indications that this was in fact the direction they should be going, they'd probably have backed out and said "no, thanks, this is way out of our league." However, that is in Evanwyl, which at the time of Phoenix Rising is a backwater location with minimal resources; in Zarathanton or any of the other major cities, there would be several Adventurers more than willing to take up that challenge.
But once you've caught your villain, you have to decide what to do with him, and that's the next section…