A bit of a follow-up to the previous installment on kobolds. (Though as I do it again, I find it somewhat more difficult to write, as 5e's bestiary likes repeating the exact same issues ad nauseum and that does make it a bit difficult to come up with new or interesting stuff about it)
Regardless, let us dive back into the works of Opineus and see if we can't suss out the truth behind his terribly researched, maliciously-motivated, and alltogether unfit for publication texts.
Our subject today will be the anurians, called here "bullywugs" by Opineus - a common name at the time, but one that has fallen out of favor and is considered insulting. For my own commentary I will be using "anurian" or "anuric", as that is the preferred exonym of that people.
Life as a bullywug is nasty, brutish, and wet.
Opineus opens with a paraphrase of philosopher Tham Hoabs. In his typical fashion, it is a quote about the wrong thing (Hoabs was specifically talking about humans), of questionable accuracy to begin with (Hoabs was dismissive-at-best in his attitudes towards any cultures that did not participate in organized states similar to his own), and presents all the (inaccurate) conclusions Opineus makes as foregone.
These frog-headed amphibious humanoids must stay constantly moist, dwelling in rainy forests, marshes, and damp caves.
Obvious, but accurate.
Always hungry and thoroughly evil, bullywugs overwhelm opponents with superior numbers when they can, but they flee from serious threats to search for easier prey.
As is typical, Opineus gives no concrete reasoning as to why a people is labeled evil, though here he seems to correlate it with hunger and basic self-preservation.
Opineus' bias about combat looks to have returned from his writings on kobolds: Rudimentary tactics such as numerical advantage and retreating from fights going poorly are given special mention as some unique, innate quality of nonhuman peoples (and an evil trait at that) - an ideology typical to those immersed in the warrior cult. Whether or not Opineus actually served as a soldier in any part of his life, I cannot say (Though I suspect he did not).
Bullywugs have green, gray, or mottled yellow skin that shifts through shades of gray, green, and brown, allowing them to blend in with their surroundings. They wear crude armor and wield simple weapons, and can deliver a powerful bite to foes that press too close.
The insistence that their armor and weapons are "crude" is a strange one. Anurians rarely have access to metals (save through trade), and so typically use wood, reed, and bone as crafting materials, but materials used do not dictate the skill with which they are used, and one need only glance at a set of anurian reed armor to recognize the skill that goes into crafting it.
Foul Aristocracy. Bullywugs consider themselves the right and proper rulers of the swamps. They follow an etiquette of sorts when dealing with outsiders and each other, subject to the whims and fancies of their leader—a self-styled lord of the muck.
A question arises here - if Opineus does not believe that the anurians' territorial claims are valid (as he clearly does not), who does he believe the swamps belong to? He does not say in this fragment of the text, which might indicate that he believed the answer to be self-evident. That particular context is lost to us.
Humorously, his description of anurian society here can be easily applied to a typical human kingdom.
Bullywugs introduce themselves with grand-sounding titles, make great shows of bowing and debasing themselves before their superiors, and endlessly vie to win their superiors' favor. A bullywug has two ways to advance among its kind. It can either murder its rivals, though it must take pains to keep its criminal deeds secret, or it can find a treasure or magic item and present it as tribute or a token of obeisance to its liege. A bullywug that murders its rivals without cunning is likely to be executed, so it's more common for bullywugs to stage raids against caravans and settlements, with the goal of securing precious baubles to impress their lords and win their good graces.
There's a great deal to unpack here, and it begins thusly.
Anurian society is based around a harem structure - a single, highly-territorial male accompanied by a group of females. Lone males may be integrated into a spawning group through allegiance-gifts to the patriarch, or will otherwise remain on the fringes of society. Patriarchs might be deposed by a challenger, and over the ages this process has become socially codified with rites and procedures to minimize collateral damage.
Opineus presents this as a sort of deficient imitation of civilization, drawing on the parallels between the anurian patriarchs and the lords' courts within the Empire. The conclusion is not worth entertaining, but there topic itself should not be avoided). The pod system of anurian life is close in principle to many human political hierarchies (that is, a singular head of state with secondary officials linked to the head by legal and cultural bonds), and it is not uncommon for anurian patriarchs to adopt noble titles and court organization from nearby human nations as a cultural defensive mechanism - an attempt at decreasing the animosity of neighboring human nations with the logic of "If we are more like them, they will be more likely to treat us as equals, and be more inclined to spare us". This has, despite Opineus' disdain, been somewhat successful, but has been a great source of friction within anurian communities - it is becoming increasingly clear even to outside observers that traditional cultural structures and practices are endangered as the patriarchs of major pod-confederations adopt further human influences to better enrich themselves and destabilize the cultural balance that had taken centuries to form.
Invariably, such fine goods are reduced to filthy tatters through abuse and neglect. Once a gift loses its sheen, a bullywug lord invariably demands that its subjects bring it more treasure as tribute.
This line is worthy of specific attention, as it is a dogwhistle playing into stereotypes of nonhuman sapients as being without culture or understanding of the value of goods or objects. Even within Opineus' own writings he cannot maintain this line of logic.
Unruly Diplomacy. Bullywugs love nothing more than lording over those who trespass on their territories. Their warriors attempt to capture intruders rather than simply slaying them. Captives are dragged before the king or queen—a bullywug of unusually large size—and forced to beg for mercy. Bribes, treasure, and flattery can trick the bullywug ruler into letting its captives go, but not before it tries to impress its "guests" with the majesty of its treasure and its realm. Struck with a deep inferiority complex, bullywug lords fancy themselves as kings and queens, but desperately crave the fear and respect of outsiders.
This is primarily a restatement of the themes of a previous segment, complete with marking a common social behavior as aberrant and evil according to its participant, rather than the action itself.
Amphibian Allies. Bullywugs speak a language that allows them to communicate over large areas by croaking like frogs. News of intruders or other events in the swamp spread within minutes across this crude communication system.
Opineus loves the word "crude", almost as much as he loves mis-using it. A language where messages can be transmitted accurately across miles in a matter of minutes is far more sophisticated than anything human communication is capable of. What can he possibly be comparing it to?
Simple concepts in the language are understandable to frogs and toads. Bullywugs use this capability to form strong bonds with giant frogs, which they train as guardians and hunters. Larger specimens are sometimes used as mounts as well. The frogs' ability to swallow creatures whole provides a bullywug hunting band an easy means of carrying prey back to their villages.
Opineus ends on something actually true, which is worth noting for its rarity. It's like being visited by a unicorn.
Final Thoughts
I have stumbled into a major limitation of this format, being that you need to vary up your source material or it's going to get really old, really fast. The 5e monster manual has proven to have overwhelming material to use, but all of it is of a monotonous quality that produces significantly worse results over time. Everything you meet is crude and primitive and evil's got very little to do with the act and more to do with who you are. It's fuckin' dull and shame on every writer of RPG material, 5e and otherwise, who regurgitates this dross without thinking about it. You're writing a book about elves, your literal job is to think about it.