While the Manual of the Planes and the Book of Vile Darkness are usually cited as third edition’s best forays into planar material, the Fiend Folio is one of only two works from this era that I consider absolute must-reads (the other being Bastion of Broken Souls). Let’s face it, third edition wasn’t really a period of invention for the game’s stories and ideas, it was far more about creating a coherent rules system and lightly exploring its ramifications. Things got far more interesting in edition 3.5, as gradually Wizards and its then-companion company Paizo pushed the game’s lore further, but the Fiend Folio was really an outlier in how much it sought to add to D&D. While I dearly wish it maintained second edition’s bountiful level of prose about each creature, in and of themselves the monsters of this volume are worthwhile even with the paltry handful of paragraphs given for each description. 

Oddly enough, this Fiend Folio doesn’t really take a cue from the first edition original, and in fact is much more akin to the Monster Manual II from back then in that much of its focus is on extraplanar entities, many of whom are in fact fiends. There’s also plenty of undead creatures here, too, as well as new fey, aberrations, and just general run-of-the-mill creatures, but roughly 50 of these monsters—dependent on how you want to count them—are planar in nature, with roughly half of them adapted from prior sources and half of them entirely new. Here’s a full accounting of who appears:

New Planar Creatures

• Abyssal Ghoul 
• Aoa
• Canomorph 
• Chronotyryn
• Demon – Blood Fiend (not tanar’ri but rather undead), Klurichir, Myrmixicus, Skulvyn (also not tanar’ri)
• Devil – Paeliryon, Xerfilstyx
• Ethereal Ooze
• Ethergaunt
• Formian – Armadon, Observer, Winged Warrior
• Gathra
• Golem – Demonflesh, Hellfire
• Imp – Bloodbag, Euphoric, Filth
• Inevitable – Quarut, Varakhut
• Kaorti (and their creations, the Rukanyr and the Skybleeder)
• Kulduruth
• Living Holocaust
• Maug
• Nerra – Kalareem, Sillit, Varoot
• Planetouched – Maeluth, Mechanatrix, Shyft, Wispling
• Shadar-kai
• Slaad – Mud
• Steel Predator
• Swarm – Abyssal Ant, Cranium Rats, Bloodfiend Locust

Planar Creatures from Previous Editions: 

• Abrian
• Bacchae
• Bloodthorn
• Bonespear
• Darkweaver
• Demodand – Farastu, Kelubar, and Shator
• Demon – Alkilith, Maurezhi, Wastrilith
• Deva – Monadic, Movanic
• Fensir
• Fhorge
• Ironmaw
• Keeper
• Khaasta
• Maelephant
• Phiuhl
• Rilmani – Aurumach, Cuprilach, Ferrumach
• Shadow Asp
• Shedu 
• Slasrath
• Spirit of the Air
• Terlen
• Varrangoin – Kinda adds some new types, but they’re still just Abyssal bats so who even cares.
• Vorr
• Yugoloth – Piscoloth, Skeroloth

And even aside from everything I listed above, if you decide to start thinking of fey as planar—as is the case with the Plane of Faerie option from the third edition Manual of the Planes or fifth edition’s core cosmology—there’s a whole bunch more.

In addition to these monsters, there’s also new prestige classes, including three just for fiend PCs or NPCs, plus fiendish grafts, maug (a new extraplanar race) grafts, and fiendish symbionts that offer some strange new options for characters—the fact that a gutworm and soul tick appear here are the type of flavorsome inclusion you’d expect far more from second edition than third. Some example statblocks for this type of fiend are also thrown into a web supplement, though what’s there is nothing really new or exciting and as such I’m not going to mention more about this again.

So that’s the general picture, which is that this book is packed with neat new extraplanar creatures and third edition statistics for old favorites. Not everything included is a winner, but that’s always the case, and the book is big enough that there’s definitely something for everyone. If I wanted to, I could just end this write-up here, feeling that I’ve summarized the work as a whole well enough, but let’s have some fun with it instead and talk about some of the more interesting new monsters and why I’m glad to see them added to the game.

Going alphabetically, even the first entry was interesting, in that abyssal ghouls bring Kiaransalee back to the forefront. She’s a minor drow deity who has had an outsized role in Planescape given that she destroyed Orcus—even the civil war in the Vault of the Drow that resulted from this received time in Dead Gods.

More generally worthwhile are the Aoa, who are “Born from the friction at rare instances when the Positive Energy Plane and the Negative Energy Plane graze each other.” Prior to now, that didn’t even happen! They’re theorized to be a neutral third energon—rule of three, anyone?—though oddly they mostly chill in the Astral and Ethereal planes. When the larger, spherical ones are attacked, they can spawn a smaller droplet Aoa, and this seems to be their method of reproduction. I’ve always loved the energons, and was happy to see the book build off their core idea. 

One of the more odd, and thus memorable, additions is the chronotyrn, large bird-like time lords with a lawful evil disposition. They have two brains and two voices, but only one head. This allows them extra actions, which is particularly deadly considering that they can cast Time Stop repeatedly. This is the type of strange, singular creature we used to see in the Planescape Monstrous Compendiums, and I even like that they come from usually-neglected Acheron.

I didn’t find any of the new demons particularly noteworthy, though I did find it interesting that the book features instances of creatures classified as demons yet not tanar’ri, which I believe is a first (or maybe second, the first instance being in the MMII? I find that book weirdly depressing and as a result am reluctant to check. Ok fine, I’ll do it…. and now I have, and there are some really dopey non-tanar’ri demons there, too. Whatever.). As this part of the game’s mythology developed, the distinction would become more relevant, though here it’s more of a footnote. The paeliryon devil, on the other hand, is extremely memorable both in art and concept, as the basic idea seems to be “what if a devil were also an overweight drag queen?” Maybe not the game’s finest hour, but as I said, memorable as hell, especially since they can kick a pit fiend’s ass. 

Ethergaunts give the game an Ethereal race of outsiders, and though they’re like githyanki/githzerai in that they’re not originally from their plane of origin, they’ve been there so long that they might as well be. Rather than a philosophical bent as per Planescape’s races, they have a more classially sci-fi outlook, coming from a more advanced culture and looking down upon the lack of progress they’ve seen from those who remained on the Prime. Unfortunately, this makes them evil in perhaps not-the-most-original way, which is probably why they never really caught on. Though wildly different in appearance, they have a lot in common with mind flayers, and so it would be hard to think of a reason to use them in all of their obscurity instead of the far more well-known monster. I like the effort, and the art, but think the entry needed some revision if it didn’t want to be forgotten.

New entries are devoted to variations of imps, inevitables, and formians, all of which are fine and dandy, though nothing to get excited about. The next truly bold addition is the kaorti, who are explorers transformed by the weirdness of the Far Realm. However, because the normal universe is deadly to them, they must wear suits made out of “thick resins and tissues” in order to stay alive. While these suits are humanoid, the insides of them are more good ol’ fashioned Far Realm weirdness: “Its skin, brownish green in color swirled with livid pinks and reds and purples, seems to be almost transparent and liquid as it slithers and runs over the creature’s visible entrails. A kaorti’s fingers are little more than boneless tendrils. Its face looks like that of a melted spider.” Even though there’s only one type of kaorti, they’re given three full pages of description, including information on how their society is devoted to converting the Prime into the Far Realm and blurbs about their armor and weaponry.

What’s more, two creatures who are kaorti creations, the Rukanyr and the Skybleeder, are given their own write-ups later on in the book. All of this combines to create the Fiend Folio‘s most fascinating addition to the planes, and once again we can see how much the Far Realm’s potential continued to interest the game’s designers. 

It’s easy, at this point, to forget that somehow the Far Realm is still not part of the game’s canonical cosmology, a fact pointed out quite recently in the edition’s Manual of the Planes. But the inclusion of these creatures, plus the continued mentions elsewhere, makes the line particularly blurry in this regard. Similarly, the Nerra are inhabitants of another non-canonical plane, the Plane of Mirrors. Like the Far Realm, this is one of the game’s weirder additions I quite liked, and the mirror-people nerra art always made me want to use them in a campaign, though sadly that’s yet to happen. They’re not quite as developed as I’d like, which isn’t too surprising given the source, though they didn’t get completely forgotten after this and made a surprise appearance late in fourth edition, plus an even more surprising appearance in Dragons of Faerûn a few years down the road. They feel ripe for more exploration, if anyone besides me ever remembers they exist again. 

As well as adding “feytouched” creatures to the game (who as of fifth edition should probably be considered planetouched, right?), there are also four new planetouched races here, all of whom are noteworthy for their particular weirdness. For instance, Maeluths are descended from dwarves and devils and no other lineage, which is a level of specificity we hadn’t seen before in planetouched. Nope, no demon or yugoloth blood here, and certainly no gnomes or halfling ancestors, just dwarves and devils. The addition of this race begs the question as to what happens with so many other possible heritages… one of which is also answered here with wisplings, who are the descendants of halflings and demons. Again, this just raises a bunch more questions. And while shifts, as descendants from Ethereal races, seem like they don’t have the same problem, it then begs the question as to who these ethereal races are, exactly (ethergaunts???). Finally, there are mechanatrixes, who “can trace their ancestry to one of the bizarre clockwork beings that reside on the plane of Mechanus.” Which I think is meant to imply modrons, but couldn’t that also be gear spirits, or inevitables, or, like, having a child descended from a large cog? I don’t know, it’s all a mess, especially when you consider that this is the third lawful neutral-descended planetouched race in less than a year! At this point, planetouched have gotten completely ridiculous, and as much as I’m weirdly fond of the art for them here, as with their entries in Dragon and the Monster Manual II I suggest pretending these don’t exist. Like… I don’t know what to say here except what the fuck, Wizards, why were you guys so crazily into planetouched back in 2002-2003? 

There’s just two more additions I want to single out. One is the mud slaad, because for some reason I just find them hilarious. Do they make much sense with what else we know about slaads? No. Do they fit in well with Planescape and the adventures with slaads there? Not at all. But I don’t care. They even have a laughable feign death ability and a somehow even more entertaining special power called “cringe,” in which for a standard action they can “cower in fear.” Opponents have to make a will save or they won’t follow through with attacking the mud slaad because they find their enemy too pathetic to strike. This may be the funniest monster ability in all of third edition, and there are a LOT of weird abilities in this book alone. 

More relevant to people who don’t choose their monsters by how hilarious they are (i.e. not me) are the shadar-kai, or “shadow fey.”

Long ago, the shadar-kai thought to preserve the world from the rising humanoid races. Skilled in shadow magic, the shadar-kai made a pact with a dark power of the Plane of Shadow to cast the world into an endless twilight in which the shadow fey would rule supreme. But the experiment went awry, and the shadar-kai were left bound to the Plane of Shadow, cursed to lose their souls in its dark depths. This shadow curse affects shadar-kai to this day, and every member of the race is engaged in a lifelong struggle to stave off inevitable doom.

As a result of their backstory, shadar-kai are fey edgelord goths with magical pain-giving armbands, another way of saying this being that they’re a group of fairy cutters. They tend to fight with spiked chains and can lose a portion of their soul to the Plane of Shadow by so much as being dazed, staggered, or unconscious. Perhaps because of their “edginess,” the shadar-kai wouldn’t be forgotten and cropped up again in Dragon and even fourth edition’s basic Monster Manual. That doesn’t surprise me, as they fit fourth edition’s general try-hard aesthetic, which I mean as a compliment to absolutely no one, and apparently this made them popular enough to reappear in fifth edition’s Mordenkainen’s Tome of Foes. I still find them largely boring, but I believe that through all of this they got fleshed out enough to gain at least a modicum of complexity. Maybe their present incarnation is no longer so cliched. Maybe.

As far as the returning monsters go, well, some of them are quite cool selections—wow, keepers are back! I love those guys!—but on the whole their descriptions are severely lacking compared to what we had before. If you want third edition stats for these folks, then great, but there isn’t really any new lore to grab onto here. Really, this is a book you get for the new material, which is fortunately plentiful. Once edition 3.5 came out, there was little reason to pick up most books from third edition, as they would soon be rendered outdated by updated works, but this is one of the few exceptions. Most of these monsters you can’t find anywhere else in the edition, making this a necessary part of any collection interested in the planes. No, it’s not as good as the Planescape monstrous compendiums, but then neither is anything else, and for once there’s a full display of creativity and wonder on display, making this by far the most interesting book of monsters from either third edition or 3.5.