esigner's Notes

This is the area where I break down the fourth wall so to speak and talk about the Savage Earth from a Game Designers point of view. The information presented here is done in a series of mini-essays, with an eye towards explaining why some things were created the way they were, as well as some hints and tips for running a successful game in the Savage Earth

Why does the Savage Earth magic system work the way it does?

How can there be a thriving criminal community in a society where the authorities can read minds and see through walls?

How can a GM overcome the obstacles of Spirit Sight and Psychic Probes?

Why did you change the cost structure on Adept Devotions?

Design Notes on Riven.

There are references to things like restaurants and cigarettes. Aren't these anachronisms?

Starting a Savage Earth campaign

Atmosphere and Attitude

The nature of Religion

Why aren't more people enhanced?

I want to play a Paladin!

How far in the future is the Savage Earth, anyway?

Enough mystery! Who or what were the Demon Kings?

OK, what about the Prometheans?

Sigh. Alright. How about those Standing Stones?

OK, if you're not going to tell me about them, how about Spiritism?

Why did you turn the Earth on its side?

OK, I'll bite. What's with the Reavers?

Besides gators and bird talkers, why are there only mammal based beasts?

Why does the Savage Earth magic system work the way it does?

The magic system for the Savage Earth was designed very carefully, with a backward approach. That is, I decided what sort of world I wanted to portray and worked backward towards a "magic economy" that could produce it.

I wanted a typical Edgar Rice Burroughs model of "savage civilization". In many of ERB's novels, cities seem to be fairly isolated. Travel is rare or difficult. One city seems to know little about the other and they are often surrounded by endless tracts of terra incognita. They also seem to lack a lot of the supporting structures that cities require, namely smaller towns, vast systems of agriculture and patterns of trade. This is an inherently difficult construct to support.

To this end, the magic system encourages small pockets of high population density. Magic needs to be limited geographically. There need to be intense pressures that keep people from spreading out. The external pressures are wildernesses filled with a variety of "monsters" that are beyond the technology of muscle and steel to overcome. Reavers are the uppermost threat of course, followed by any number of chimeras, barbarians, riven, mutants and so on. In short, conquering the wilderness is beyond the means of any but the most aggressive and toughest of people.

The magic of adepts is very effective at reducing the hazards of the wilds. Adepts can repel reavers and produce artifacts capable of long term reaver protection. They can produce warriors, weapons and engines of destruction that can overcome most barbarian, mutant and riven threats. Thus, there is a great tendency of people to cluster around adepts for security. By making the training of adepts dependant on arbitrarily placed Standing Stones, they are anchored geographically. This is why there are a small number of large cities (each founded upon a group of Stones), instead of a large number of smaller towns, each with its attendant adepts. By designing a system in which magic fades rapidly as it gets farther from its adept source, cities are made more compact and less likely to spread or colonize.

Initially, the problem of food production becomes paramount. How can these cities produce enough food to support so many people if the lands around them are unsafe for agriculture? The answer is to make food production also dependant upon adepts. Over many years, adepts have developed strains of crops whose yield and nutritional value far surpass even the highest-producing of modern plants. Combined with making most of the cities dependant upon the sea for protein this is sufficient to support an otherwise unlikely population.

How can there be a thriving criminal community in a society where the authorities can read minds and see through walls?

This is one of the most difficult problems to overcome. Once you start looking into the logistics of the problem, it is not insurmountable however. Part of the solution lies in the way the city is laid out. Adept influence and presence decreases as one gets further from the city center. In Tallon, the city is rather heavy-handedly divided into high-magic and low-magic halves. Thieves and muggers operate much better in the bad half of the town, where there are far fewer adepts and police and where there is virtually no artificial lighting. Criminals also tend not to victimize adepts for fear of reprisal. The bulk of criminals therefore prey on those least able to defend themselves, and consequently have the least to steal. This leads to a cycle of desperation and brutality encouraging tougher, nastier criminals. For game purposes, this makes the average criminal a good match for the average constable, and the constables are greatly outnumbered. The police tend to guard the areas of town that are most defensible and the wealthiest and to let the rest of it police itself with private guards, mercenaries and the like.

It takes a truly elite criminal to pilfer and otherwise threaten the half of the city where the magic is highest. For ways in which they might overcome these obstacles, see the next essay.

How can a GM overcome the obstacles of Spirit Sight and Psychic Probes?

Another toughie. Adepts can see through objects, detect personal danger and read minds. They would seem at first glance to be virtually superheroes in a world of normals. There are a number of conventions that can reduce the utility of these advantages.

Firstly, always remember that Spirt Sight is not N-Ray vision. The information gained is very general. Identification of specific individuals is hard. Just because an adept says, "I am scanning the crowd looking for someone with a sword," doesn't mean that to them the world looks like a dark blur with all swords shining like beacons. Scanning the rainforest looking for a gator doesn't mean the gator stands out like the jungle didn't exist. Adepts see all spirits, not just the ones they are interested in. The contrast that one gets with sight is not a good analogy. Looking for a gator in a forest is not like looking for a red square in a field of blue circles. It's more like looking for a red square in a vast and confusing array of shapes and colors, or listening for the oboe in a full orchestra. Never let an adept use spirit sight like a tricorder.

Spirit sight is further limited by layers of dissimilar materials. Finding gold inside a wooden chest is fairly straightforward. If that wooden barrier is backed by even the thinnest sheet of lead, that's a -2 penalty to the PER roll. If the lead is backed by a velvet liner filled with cotton padding, that's two more -2 penalties. By creating such a chest, the person who wishes to conceal something will have given the scrutinizing adept a -6 to their PER roll. A failed PER roll will only reveal the contents to the degree the roll is missed by. Therefore, missing a roll by 3 in the above case will only reveal that the wooden chest contains lead. Merchants will tend to use such chests or wear similarly constructed pouches. Even if two materials alternate (leather/wool/leather/wool), each layer grants a penalty. An oil cloak used by a thief might have two or three layers to conceal weapons or even general identity.

Never forget to use range modifiers for PER rolls. You can ignore them if the plot would be advanced by doing so, but always remember that distance is a good negative modifier.

Psychic probes and Detect Hostile Intent present their own difficulties, but both can be countered by similar techniques.

Some people have the aptitude to learn shielding. Mental Defense is used as a defense against all adept abilities, including these two. A normal with a Mental Defense of 10 gives the detecting adept a -2 penalty. A truly psychotic person might also give off no aura of danger if they do not believe they are causing harm. This would more likely be represented by a Psychological limitation and used as a plot device, but it is possible.

A person might resist probing by special preparation. For instance, they may have a psychic alteration of some sort that is triggered to collapse when probed. This would again be more of a plot device as such preparation would be possible only through the actions of a highly skilled psychist.

Another possibility is a complete body covering. Although the brain is the organ of rational thought, the Psyche emanates from the body as a whole. If the person were encased head to toe in a body covering, the layers of intervening material would provide the modifiers listed above, i.e., -2 per layer after the first. Of course, any eyeholes would have to be extremely small, and a GM would not be out of line in giving a similar PER penalty to the person in the body stocking. Also, such garb would be so cumbersome and uncomfortable in the equatorial clime of the campaign that it would be only the most temporary of tactics.

Any and all of these techniques could be employed by thieves, assassins or other criminals. Or perhaps just paranoid players.

Beyond these techniques, there are further limitations that a GM can use to stop adept abilities from short-circuiting a plot.

Always bear in mind that the vast bulk of adepts have little beyond the lowest form of Spirit Sight. Use Masters and Grandmasters where needed, but the run of the mill adept won't have danger senses, heightened characteristics or anything like that.

Also, although judges are required to be psychists, the available pool of Master Psychists in a given city is very small and might not even be enough to cover the required number of offices. As such, the Archon or other appointing body cannot be too choosy in the character of the person they appoint. A judge could quite easily be corrupt, receiving kickbacks from a criminal group to turn a blind eye or even give a false witness on a probe.

Why did you change the cost structure on Adept Devotions?

The adept devotions are periodically revised or refined as game play reveals weaknesses in the design. The most recent change was in the minimum costs. It was my original intention to limit the number of psychists in relation to other varieties of Master. After all, they were the ones with the greatest potential of wrecking a story line. In practice though, this meant that all psychists were extremely powerful. I couldn't have a Judge for instance with just a limited ability to read or alter minds. It might be useful to have more weak psychists and a few poweful ones than to have them all be powerful. So i reduced the minimum Multipower reserve to 40 across the board, and instead raised the minimum for having multiple devotions. This didn't invalidate any already-purchased characters and made the devotions a littl more flexible from a dramatic point of view.

Design Notes on Riven

The place of riven characters in the campaign has evolved somewhat through play. Initially, they were there to fulfill the part of orcs play in a traditional fantasy game: an enemy a hero may freely kill with no moral taint. In The Lord of the Rings, Aragorn never sympathizes with an orc or goblin. Even his parley is more of a "get lost or we'll kill you" speech. They were designed to be quick and dirty opponents that a GM could use to attack players in the wilderness. A melee could ensue without players worrying "am I doing the right thing?"

In the course of game play, they turned out to be too alluring as a player character. Their unique and potentially exotic nature allows a player a lot of creativity. The few players who played riven characters elicited such pathos from the other PCs that viewing riven as wholesale monsters became unpalatable. Also, when you get right down to it, they are ultimately victims. They did not ask to become what they are. Killing them seemed more like executing the wounded.

Thus several changes were implemented in the course of play. Firstly, a reason was found to make riven into social desirables. They serve the city of Tallon (and perhaps others) in a tactical sense. Through a strange quirk of spiritology they can sense the invisible assassins sent forth from the Celestial City. Continued exposure to riven in a useful capacity did much to change public attitude. A riven character is now more possible than when the campaign began. A GM starting fresh in the Savage Earth may want to place this event in the campaign's past, so that new players can play riven characters.

Although there are still bands of riven in the wilds, these are now more accurately portrayed as savage people who have banded together for the express purpose of brigandry or ogreism.

The role of "orcs" has now been subsumed by gators. My advice is to never exhibit a sympathetic gator character. They are villains.

There are references to things like restaurants and cigarettes. Aren't these anachronisms?

Not at all. The Savage Earth is not a medieval fantasy, or even a pseudo-medieval fantasy like D&D. It could best be described as a post-apocalyptic fantasy. In order to distance the campaign from the medieval European feel, some social and technological constructs have been allowed to survive. Basically, it was a good enough idea that people didn't forget how to do it.

Restaurants are one thing. They bear a great deal of similarity to a modern restaurant, save that the fare is probably not as varied. A patron might be able to choose between 5-6 basic meals, or in a nicer establishment, request a specific preparation. Restaurants will not have printed menus; the server will have memorized the venue. Food preparation time can be lengthy in the case of more elaborate meals, so a restaurant visit can take a couple of hours.

There is even the equivalent of fast food. Booth vendors in market places and large busy public squares can sell meat or fish pies, rice wrapped in edible leaves, hot potatoes or raw fruits and vegetables. These can be bought on the run.

Tobacco has survived and in Tallon can be inhaled through pipe or wrapped paper or leaf, generally called a "roll-up". Matches are common as well, though they are expensive enough that many will prefer either flint and tinder or some existing fire source such as a lamp to do their lighting up.

I have retained some standard fantasy terminology such as "tavern" or "guild" although the latter might be better referred to as a labor union.

Beyond seeming anachronisms, Merikians also have some mundane technology that is quite advanced

There are clocks, both traditional clock-work and morphically powered. Merikian oil lamps are marvels of waterproof technology and will continue to burn if dropped or rolled. They will even burn underwater until the oxygen is depleted. Oilcloth is a textile that is complete waterproof, but not greasy to the touch. Neither is it particularly uncomfortable. It is so light as to nearly "breathe". Although spirit-harvested and initially spiritually enhanced, Merikian crops are unparalleled in their yield. There are even the equivalent of tractors, though these are used only on the largest and most wealthy of farms.

Starting a Savage Earth campaign

A GM is of course free to use any, all or none of the material presented in this campaign setting. They should in no way feel constrained to include the events described in the Chronicles or the Tales. In fact, the Chronicles and the Tales are fairly exclusive in that events in one rarely if ever intrude upon the other. They certainly could be taking place in the same continuity, but they don't have to be. Certain NPCs are used in both campaign, but these could be seen as campaign NPCs, available for anybody's game. Thus anyone's game might include the Vice-lord Harker, but the DNPC Jareek would only be found in the Tales. Likewise, the PC Tira is likely only to adventure within the Chronicles.

This campaign guide should be looked at as a common starting point. Take what works and ignore or change what doesn't. Feel free to kill off the Rivermaster in your campaign; he'll likely be around in someone else's.

Atmosphere and Attitude

The Savage Earth models a certain barbaric genre of fiction and fantasy. It would be a mistake to impose modern morals and ethics upon a given situation, since the world does not operate by those principles, even by way of lip service. Within the context of the game world, all people most definitely are not created equal, there are no inalienable rights, and civil liberties are words that don't really make sense when used together. A common mantra heard during a game is "Well, it's a Savage Earth.

Corruption exists at any level and is a fixture of the way things work, not a scandal to hide. Your ability to be thrown in jail or roughed up by the police is directly and inversely proportional to your social status. Nobodies have few protections. The rich and powerful can get away with quite a lot. Who you know is paramount to success. The society has a built-in social structure intentionally modelled after the Elizabethan concept of the Chain of Being. There is a place for everyone, and everyone should be happy in their place.

All that being said, PCs are highly forceful and ambitious people and are not required to just sit back and accept their fate. They are heroes, and are usually more than capable of forging their own destinies.

It is tempting to make the wilderness savage and brutal and the city tame and well... civilized. To some degree this is true. The city is a much safer place to live than the wilds. But the safety is a matter of degree only. Death can come just as quickly and unfairly within the walls of Tallon as in the deepest jungles of Nunavut. If anything the danger can be greater simply because the jungle is fairly honest about its dangers. Everything out there pretty much wants to kill you or eat you. In the city, you must add treachery and deceit to the list. However, those who keep their heads down, travel by day and don't make waves (i.e., not PCs) are safer within the walls.

Never forget the danger. Never forget that nobody gives a darn about you but you, your family and friends and the very rare stranger. Never forget it's a Savage Earth.

The Nature of Religion

When running PCs or NPCs who are clergy, or even involving the Church in a plot line, a GM or player should keep certain concepts in mind.

First, the Church derives its authority from the same source that is the foundation of the entire Merikian society, government and technology. There can be no doubt of the power behind its philosophy since without Spiritism, the cities would collapse. The Church is real, and it is manifest in every aspect of Merikian life. There are no doubters. Now it's true that someone could have a beef with the Church's interpretation of the teachings of the lawgiver, but there is no question that their entire way of life is dependant on the Spiritist way of thinking.

Second, the Church has far more in common with ancient religions than the modern "moral" religions. That is, the Church is a source of power, tradition, philosophy, social order and devotion, but it is not a source of morality. There is not moral ideal from which good intentions and just living flows. The Church is not about love or faith. It is about duty and honor, tradition and social order. A person seeking comfort in the church would be seeking confirmation that they are living their lives or that events are unfolding in accordance with a divinely-inspired order, but there's no sense that this order is for anyone's personal well-being. It's about survival. The church represents a way of living in a Savage Earth that works.

Individual priests may be pious and generous, or greedy and acerbic. There's nothing that says you have to be nice to be a priest. But you must be willing to give your life to public service.

Why aren't more people enhanced?

This question is actually answered within the main text, but bears mentioning here. The game design reason of course is to keep stat inflation down and to prevent everyone from running around with superhuman abilities. The game would quickly devolve into a situation in which the only people who mattered combat-wise were those who had adept enhancement. Non-enhanced people would be severely marginalized. Enhanced people are the rare exception for players to encounter.

Although explained in greater detail in the link above, it basically boils down to a limited number of adepts and ley lines, which would be better utilized for civic purposes, and the metagame construct that a character needs to buy a knowledge skill for anyone they plan to keep enhanced long term.

I want to play a Paladin!

Well, who wouldn't? Actually, if a groups is sufficiently mature enough to handle a situation in which one character vastly outshines them in terms of physical and mental prowess, right from the start, there is no problem with allowing a starting Paladin. They would not even need to pay for the enhanced characteristics, since they are artificially boosted. They would need to abide by the social, physical, and psychological limitations imposed upon paladins, however. Some of these would make game play difficult.

A paladin is geographically limited to the near proximity of their Grandmaster. The Grandmaster would be a huge fixture in their lives, requiring the GM to make this a recurring (more powerful) NPC. They would not be able to leave the city and go adventuring for instance. They are unswervingly loyal to their master. This loyalty is at the highest level; they cannot even make an EGO roll to disobey. Their devotion is so great that Paladins are interred along with their Grandmaster after the latter's death. Immediately after. Yes, they suicide short after losing their patron.

Paladins are best used as NPCs, unless the focus of the campaign is upon a Grandmaster and his retinue of paladins, these being the player characters.

How far in the future is the Savage Earth anyway?

This is kept deliberately vague. Part of the reason is that the theories regarding how long buildings, roads and other artifacts would stick around are often contradictory. The unclear timeline helps to resolve any problems by sidestepping them. However, there are some clues in both the campaign guide book and gleaned during play:

Echomen from Saginaw (ghosts or memories of long-dead people possessing modern bodies) have claimed to have ranged from the mid-twentieth, well into the twenty-first century. None of them have seemed to be familiar with the term Demon King.

Vagrant is a character apparently preserved intact from the early to mid twenty-first century.

The calendar of Tallon is undependable, but seems to be around 300 years old. It was not founded during the time of the Demon-Kings.

The Demon Kings were said to have reigned for a "timeless time". There is no good explanation of what these words mean.

Areas of the city of Tronto were unnaturally preserved. As if they had been abandoned only decades ago instead of centuries. The general history of the area indicates that it is an ancient ruin, regardless. This is an unexplained phenomenon, but may have something to do with the fact that the Great Lakes stone group seems to focus on time-based spirit manipulation.

Enough mystery! Who or what were the Demon Kings?

Get used to mystery. The Gamemaster has a good idea exactly who and what they were, but this is one of the central mysteries of the campaign. Revealing it would reduce the terror and awe they inspired to a mundane, dry historical fact. It would be best if each GM had their own idea and acted accordingly upon it.

However, like the timeline, there are clues within the text and the chronicles.

They seemed to have few physical limitations. They had a technology capable of altering the rotational axis of the entire earth without destroying all life on the surface. Their artifacts seem to be indestructable and orders of power greater than anything achievable by current Savage Earth Spiritual technology. Nevertheless, they are all gone and were apparently defeated by the Prometheans, whom tradition says were humans who learned Demon King secrets.

They do not seem to have operated in groups. Each Demon King court appears to have been the province of a single entity. Given their distribution across the lands so far explored, their number were probably below a hundred, if that.

They seemed to be named after human concepts, sometimes from literature or mythology. Sometimes their names seem to come from a region. Thus names like Nemo, Great Cthulhu or the Wendigo, or one from the Old South called the Colonel or from Southern California called Imago. The reason for this is unknown, but presumably the names were adopted at some point.

The only known entity (Arthur) to have claimed to be a Demon King was a notorious liar. Although undeniably possessed of great personal power, any claims he made are to be regarded with a jaundiced eye. He did not seem to have cosmic ability, though in terms of personal power he seemed unassailable.

OK, what about the Prometheans?

For all intents and purposes, the Prometheans are to be regarded at face value. They were slaves who rebelled against their masters, overthrew them, laid the foundation for the great cities and the technology/philosophy of spiritism and then disappeared. Actual details again are vague, so that the GM is free to improvise upon history.

Some clues:

They appear to have been human. Surviving accounts all refer to them as human. Some very old beings (Arthur, the priest of the Seraphim) refer to them as human and seem to corroborate their story.

The stones they left undeniably work and allow the creation and sustaining of the great cities. They are often said to have had an inscrutable plan. Arthur corroborates this, for what his word is worth. He refuses to elaborate, however.

Although Prometheus is credited with the revolution, it appears that he may have had help from existing Demon Kings. He certainly did not act alone.

From a campaign standpoint, they fulfill the role of gods in a fantasy genre. They are the Founders of Civilization, the well spring of the culture. They are more similar to the old Irish Tuatha de Danaan, who defeated the Fomorians, and then were themselves defeated by the Goidelic Celts. More supernatural than divine, but definitely worth reverencing. Neither the Prometheans nor the Demon-Kings seemed to have claimed to be Creators. That seems to be an even more enigmatic thing called the Deus.

In game terms, Deus, of course is just Latin for God and represents a creator who could just as easily be Yahweh or Brahma or Uranus or any number of creators. I placed the concept there when I realized the current cosmology needed a Prime Mover and an Ultimate Reality. The Demon Kings and Prometheans may have been supernatural, but they are not generally regarded as of divine origin. Deus is mentioned often in scripture, but little substantive is said of him. For all the Merikians know, he made the universe and then fell asleep.

Since Morality does not feature in their religion, there is no concept of Heaven and Hell. Departed souls are said to join with Deus. Rewards and punishments come in this lifetime.

Sigh. Alright. How about those Standing Stones?

Mysteries, mysteries and more mysteries. The Standing Stones were created from a game designer's perspective to enforce the pattern of "savage civilization" mentioned above. They are a way of anchoring the cities and keeping them from spreading and colonizing. They are necessary for the learning of the advanced magic that keeps civilization working. They also serve to give authenticity to the religion. It's not a bunch of made-up mumbo-jumbo.

Arranging them into groups that teach slightly different magic is mostly a way of keeping far-off lands from being homogeneously familiar.

They also form a good source for adventure, legends and tall tales. Finding a set could mean you might become the founder of a new city!

OK, if you're not going to tell me about them, how about Spiritism?

Any magical set of spells could have arisen out of the magical restrictions and requirements that I induced from the world I wanted. Why Spiritism? Why not fireballs and lightning bolts? The answer to this lies in a previous campaign treatment I developed. I had originally wanted to create a world called the Borderlands, where all fairy realms lived. Oz, Wonderland, Atlantis, Neverland were simply geographic locations in this bizarre other realm. The campaign was going to revolve around displaced people from the real world of the thirties trying to keep the secrets, powers and people of this realm from falling under the dominion of a large contingent of Nazis who had discovered the means of entering the realm.

The campaign was stillbirthed however, when a friend began running a very similar campaign. So similar that I was convinced he had read my mind. He was brilliant enough to find a way to include Romans and Dinosaurs. Rather than run a nearly identical campaign, I decided to salvage what I could and create something different from anything anyone else was running.

The magic system I developed for the Borderlands was designed to explain the existence of talking animals like the White Rabbit and the March Hare and animated people like the Scarecrow and the Tin Woodman.

Spiritism evolved from that and was influenced by the novel A Barnstormer in Oz, by P.J. Farmer as well as concepts in some of Terry Pratchett's Discworld novels. Some intense researched turned up further sources, but they are a bit obscure to go into here. (I.e. I've forgotten.)

Why did you turn the Earth on its side?

One of the concepts that seems difficult to grasp is the new orientation of the earth. It really should be introduced better. People who have played for years will sometimes light up their eyes and say, "Oh! I get it!" when they recognize what has been done with the map. Originally, I was just going to use plain old earth, with perhaps some subtle alteration of coastlines due to horrific flooding or something. Then a friend reminded me of an idea I had long had in the back of my mind for a fantasy map. Back in the Stone Age, when I was in college, the campus library had a huge globe, nearly three feet across, that sat in a mount that allow it to be easily viewed from any angle. Someone had been playing with it early and I was looking at the Arctic Ocean. I realized that if that sea had only been more temperate, it would have been like a giant Mediterranean, the source for much trade and adventure in the Classical World. It has a zillion islands, two facing continents, and a really unfamiliar coastline.

I had been looking for a civilization and climate-altering disaster and when my friend reminded me of this global trick. So I said, "hey, why not?" It makes the familiar into something very mysterious and new. Eastern Sahara is now arctic. The world has tropical fjords. Antarctica is equatorial. The eastern seaboard of the United States is arid desert. It does a very good job of making the world as mysterious to the players as it should be to their characters. Admittedly, tipping the earth was somewhat beyond the means of what I had originally envisioned for the Demon Kings, but it wasn't a big stretch to make them so powerful, since they were all gone.

I have done my best to work out the new climates and have extensive maps showing currents, high and low pressure areas, wind and precipitation patterns and so forth. I have done my best to make it realistic.

It is of course impossible for dense jungles to grow upon the Canadian Shield, especially in any realistic time frame. There's no topsoil to speak of. The answer to this design problem lies with the reavers.

OK, I'll bite. What's with the Reavers?

The reavers serve several purposes in the campaign. They are the source of all the riven and fantastic creatures that populate the world. Evolution couldn't create such variety in such a short time. They are also the reason people can't just spread out and colonize the wilds freely.

As a source for mutation, they do far more than make monsters to fight. They alter whatever they touch, creating plants that can break down basalt in generation and allow jungle to bloom. Or perhaps they altered the land itself to create fertile topsoil? It really doesn't matter, in this aspect they are a plot device to explain otherwise inexplicable diversity and growth.

The other function they serve as an insurmountable threat. Human beings are ingenious creatures that when using applied learning and tools are more than a match for the greatest monster ever made. Reavers are beyond human understanding and beyond their ability to destroy. At the very best, adepts (remember them?) can turn them a bit. This ability should be a clue as to the origin of reavers. Also, the cities and artifacts that adepts make are deterrent to reaver intrusion. Reavers reinforce the plan of the Prometheans in this way. Accident or Design?

Besides gators and bird talkers, why are there only mammal based beasts?

Anthropomorphic animals exist in the campaign for several reasons. First, as mentioned above, the previous Borderlands campaign featured them, and I had already done groundwork on character packages and such. I also wanted my fantasy campaign to have a variety of player races, since they're fun to play. At the same time, I didn't want standard fantasy tropes. Elves and Dwarves just wouldn't fit. Likewise, I didn't want to make up new races wholecloth, since that would be overwhelming to new players. So talking animals it was. By designing them so that they had the exagerated characteristics attributed to their root stock, players would have a rough and ready guide to the rae as a whole. Foxes are clever and tricky, dogs are loyal, cats are independent and so forth.

A great deal of thought went into deciding which animals could be made anthropomorphic. One of the paramount problems was how to differentiate between animals you eat and animals you talk to. I wanted to avoid a feeling of cannibalism at all costs.

This is the entire basis for the "no hooved animals are talkers" rule. It gives a good guideline that allows people to raise and eat cows, sheep, pigs, etc without worrying about having to ask, "pardon me, do you mind being eaten?" first.

I extended the classes of talking animals to reptiles since gators seemed like such good monsters: armed with teeth and armored with scaley hide, ravenous eating machines. Logically, birds are more advanced than reptiles and should be represented among the anthropomorphic crowd. So birds are in there. Birds are naturally less humaniform than reptiles (having wings instead of forelegs), so they are far more often talkers than full beasts. They also serve a valuable purpose within the game. Birds are efficient spies and messengers. They must be used carefully and only when the plot requires, or players will become too paranoid.

I have had a very few amphibious talking animals, since I really didn't want to muddy the waters any more between talkers and non-talkers. Eventually the flow of the story would bog down as people would be (rightly) cautious about every animal they met or ate.

Fish in particular will never be talkers. The economy of Merikia depends on fishing, and there's no way to interrogate every fish brought up in a net.

I came up with the idea of talking beasts wearing clothes as a signal to all other beings of their protected, uneatable status (at least to civilized folk). Again, I want the distinction to be immediate.

There are many riven who have attributes from throughout the animal kingdom, including insects, worms, fish, molluscs and so on. There are even some hooved mutants like satyrs or devil merks, but they would in no way be confused with beasts.