I'm continuing the adventure path design! With a powerful villain now in play, it's time to think about lesser minions and lieutenants that will serve as the foes for lower levels, leading into the final fight against Treerazer. 

So let's think about sub-villains, and the foes the heroes will face at lower levels.

I've already boxed myself in a bit with my super-short word count, as I can't rely on lots of lengthy stat blocks for villains with class levels--or, as Pathfinder Second Edition uses them, class-typed abilities. Paizo doesn't really do "hobgoblin clerics" or "boggard rogues" any longer; instead, the humanoid is rebuilt to match the necessary abilities of its new (higher) level, and it's given a name to match its role or nature, rather than its class. They might create a "hobgoblin death priest" with some divine spellcasting or "boggard swamp scout" with sneak attack. Regardless, these advanced creatures take up a lot of word count, and I've got few words to spare. I can't, for example, decide that the heroes face off against human demon cultists or elven forest corruptors at every level. So let's instead look at what the Bestiary gives us. A few things jump out at me:

* Low-level demons are sparse. Treerazer is a nascent demon lord, so demons as sub-lieutenants make a lot of sense. But these can't really come into play until higher levels. The only low-level demon in the Bestiary is a Level 1 quasit, and the next most powerful is the Level 7 succubus, which has a specific role that isn't often as a leader or a ranked minion. Pathfinder First Edition had useful demons in these low levels, like blood demons, but I'll have to do without them. The lower-level threats must be non-demons. But that's okay; it's fine to push the serious demon troubles until later in the campaign.

* Dragons aren't off limits. Many RPG companies, including Paizo, put dragons in a strange spot. They eat up tons of pages in the Bestiary, yet they show up so rarely in adventures that they might as well not be in the Bestiary at all. I'm going to plan on using lots of dragons of different types; the evil dragons are very likely to be susceptible to the promises Treerazer can make. So I'll use dragons. Dragons come in a variety of levels, and are useful across the adventure path. But dragons are often masterminds, and they need tough minions. You know who makes great minions, and also come in a wide variety of levels? Giants! I think I'll default to "dragons with giant minions" as a subset of villains here. Maybe most of them work with Treerazer, but some of them don't, to get some intrigue going. A scene where the heroes can negotiate with a powerful dragon, like for information, seems neat. Treerazer is chaotic, so perhaps he's made some great promise to dragons that he doesn't intend to fulfill, and alerting the dragons to Treerazer's betrayal makes for a late-game victory.

* Devils pose a problem. The Bestiary has lots of lawful evil fiendish creatures, particularly devils. And, unlike demons, devils *do* have useful minion types in the low- to mid-level range (like bearded devils and fury devils). But devils and demons rarely get along. Devils don't make great minions for Treerazer. But that doesn't mean they can't be villains! There could be an entire organization of evil fiends trying to slip in and take advantage of the chaos Treerazer is causing. This would be a parallel evil organization, but one the heroes defeat before confronting Treerazer. With a Level 20 pit fiend at the top, this might be something the heroes finish when they're 17th level or so. I want to make the devils even more distinct from the demons in this adventure path; while the demons serving Treerazer maraud around the wilderness, perhaps the devils are more stealthy and urban in their approach. Maybe having a whole city tip over to diabolic control in the mid-levels of the adventure path would work; let me keep that in mind. 

* Good creatures can be bad. When deciding which monsters are useful for an adventure path, there's often whole swaths of Bestiary entries that seem off-limits: angels, benevolent fey, and other good creatures. Few adventurers sign up to butcher herds of unicorns. Here, however, I've got the opportunity to use lots of these normally-good creatures as enemies: fey might be corrupted to work for Treerazer in his pollute-the-forests master plan, and arboreals (formerly treants) might be working for him as well. In fact, some evil fey and arboreals who have embraced evil might make some good villains in the low levels. 

* Unrelated evil exists. Not every encounter must drive toward the main adventure path plot. The heroes can also go on side trips to rescue people from duergar slavers, or confront an undead uprising, and so on. There will be plenty of room for side missions like these, although I'll try to make tangential connections to the plot when feasible. 

So, let's put some of this together with some specifics. It might be better to work backwards.

* 20th level: Treerazer is the ultimate foe.
* 17th - 19th level: Powerful demons (like balor and mariliths) are the high-level foes, along with some powerful dragons and their powerful giant lackeys). Perhaps some linnorms, which combine "evil" with "dragon" and "wilderness" quite well.
* 15th - 17th level: In addition to the demon/dragon threat, the heroes must confront the devil leader here too.
* 11th - 14th level: This is a great place for lower-power demons, like glabrezus and shemhazians, to appear as villains. High-powered dragons work here, as well, and there are plenty of giant minions (and golem minions) for them to have. This could also be good levels for other opportunistic evils, like undead, to appear.
* 8th - 10th level: Although some vrock demons might fit in here, everything from this level and below is probably very demon-light. Arboreals, evil fey, and other such villains are better fits here. The more powerful elementals fit in this range. So I see some strong wilderness exploration here. 
* 4th - 7th level: From a narrative perspective, I want the heroes to understand the overall threat and what's at stake here. So a single powerful demonic foe, like a vrock or a succubus, makes sense. Perhaps some devil foe offers clues, as well. If evil arboreals are a foe, the heroes probably face their regent in these levels.
* 1st - 3rd level: These are where the heroes get their first taste of the troubles, and must rely heavily on NPCs. These are also the levels where NPCs can often appear as villains, as changelings, tieflings, dhampirs, and so on that appear in the Bestiary make good low-level foes. Lower-level forest foes also make sense here.

Okay, that's a good framework! I'm sure it will change as I dig in further, but it lets me look at any given level and say, "here's what's going on at that level." So that's what I'll do next!