Planes of Law

 Whew!

For 20 bucks, I got a pretty hefty amount of lore. I've now read through the Planes of Law supplement from 2nd Edition Planescape (well, I think I still need to read through the monster descriptions, but I've gotten through all the plane-specific stuff.)

Luckily, for a 2nd Edition book, this is really lore-focused, and while there's talk of spell types and things like spell keys and power keys and such that I really don't understand at all, overall it's mostly just descriptions of the planes.

Planes of Law covers five of the outer planes - Acheron, Arcadia, Baator (the Nine Hells,) Mechanus, and Mount Celestia.

Given that 5th Edition has only really gone into detail about the Nine Hells and a little in the Abyss (I think they're the only two that get descriptions of multiple layers in the Dungeon Master's Guide,) it's nice to get a little more detail for places like Arcadia and Acheron, which I could imagine being sort of swept aside especially because they occupy a sort of hybrid ground between alignments.

Indeed, Arcadia actually has some really cool intrigue - of its three layers, the third one has actually gone missing, absorbed into Mechanus. The explanation for why is a great example of how you can make dangerous antagonists even in the upper planes - the details of which I won't spoil here.

A fair number of the regions described in the plane descriptions are actually about deities from real-world mythologies. For example, Heliopolis is the realm of Osiris, Ra, Isis, and Horus, and sits within Arcadia. I think more recent D&D stuff has tended to de-emphasize the existence of real-world mythology in its canon.

As an aside, a long campaign I was in had, as one of its central plots, the fact that our paladin worshipped Athena, despite being from the Forgotten Realms. Rather than simply having Athena influence another world, though, our DM created a complex interplanar conspiracy involving people who wanted to conquer Toril and made the paladin's mentor some kind of odd construct - one of many.

Of these five, I actually think the physical structure of Acheron is the most interestingly outlandish - a realm of giant iron cubes (and other shapes, but mostly cubes) that bang around across the plane. Here one also finds Hassitorium, which are moving fortresses that can move because failed soldiers are magically bound within the walls, meaning you could have the party see one of these fortresses moving toward them on hundreds of normal human-sized feet.

I will say that the mechanics of the planes make the idea of a D&D afterlife a little less comforting - even in the Seven Heavens, you might get killed by a rockslide (though petitioners - the spirits of dead mortals who go onto the planes, will become one with the plane when they die there, which is ultimately the goal most of them strive for). Still, you need stakes for these locations to be the settings for the stories you tell. Essentially, each plane really asks you to commit to a philosophy. Heaven's not the reward so much as signing up for a difficult and long journey to perfection.

Likewise, of these five, I really think the Mount Celestia's the only one that really seems all that appealing of a place to wind up - even though Arcadia leans toward good, there's a bit of a cultish authoritarian thing going on there. Mount Celestia, being just as lawful as it is good, also demands a lot of its inhabitants, making me wonder if Elysium's really the best place to wind up.

One thing that's interesting about the book is how clearly it was written in the wake of the Satanic Panic. D&D had become this lightning rod for people worrying that young people were worshipping the devil (while I think most people were just concerned with the ideas that the game was giving kids, rather than thinking that the spell descriptions were literal and real, some nut-jobs genuinely did think that the game taught kids how to summon demons). TSR, the company that owned D&D at the time (I believe Wizards of the Coast, which made Magic the Gathering, bought it in the late 90s) was trying to at least de-emphasize any explicit references to demons and devils, and I think it's also for this reason that the books speak of "powers" rather than "gods."

Indeed, the description of Baator (which, to be fair, gets parenthetically referred to as the Nine Hells) claims that the Lords of the Nine are mostly unknown except for Levistus, and presents it as a huge mystery as to who is actually in charge of them. Of course, in 5th Edition, we've got a definitive list. Here, Devils are "Baatezu," and Demons are "Tanar'ri." Apparently prior to these changes, what we now know as Yugoloths were originally, confusingly, called "Daemons." That one stuck. I'm actually tempted to keep these terms if I were to run a Planescape game - indeed, in my headcanon, the Infernal word for devil is baatezu. The Abyssal word for demon could then be Tanar'ri (though I might not go with this latter possibility as I think it's potentially really interesting if Obyriths and Tanar'ri are separate types and generations of demons).

Each plane section has a few adventures, though these are very sketchily outlined - which I imagine would be a bit of a pain for someone running this back in the day, but its sketchiness actually makes translating the adventures (really just outlines that are one or two pages long) into 5th Edition potentially a lot easier.