Last time, I presented the first adventure in the adventure path I'm writing. Today, I want to talk about how to end it. I haven't yet put this together, because I think it will depend a lot on how the 19th-level adventure goes, but I want to put down some thoughts about the 20th level finale of this campaign.

* It need not have 12 encounters. I've been building every chapter with 12 encounters to make sure there's enough experience for the heroes to level up for the following chapter. Since this is the last one, there doesn't need to be as many as 12 encounters. There should be a least a few, however, so the heroes get to stretch their muscles at the top end of the game and use those nice capstone abilities they've earned. I'm going to shoot for 4 or 5 encounters, none of which are more difficult than Moderate difficulty except for the final fight.

* It should tie well to the adventure before. Each adventure in an adventure path should tie to the one after and before it, of course, but the very last adventure should have a much tighter tie. There ought to be a "whew, we're done" moment at the end of the 19th-level adventure, then an opportunity to rest and level up over not much more than one night, then swing into the action of the finale. The finale should be at substantially the same location as the prior adventure.

* There should only be one solo fight. The only solo monster the heroes should face in the finale is with Treerazer, the ultimate foe of the campaign. Other fights should come in groups of at least 2, and maybe more, so narratively Treerazer is the only one who stands alone against the heroes.

* The final fight should seem to be a challenge. The last fight should be hard, of course. There's something to be said for making climactic battles appear nearly impossible but actually be quite winnable throughout an entire campaign, but nowhere is this more true than in the adventure path's final boss. The heroes should feel outmatched, but actually have lots of tools to succeed unless they're very unlucky or make a lot of poor decisions. Normally, this might be making the encounter tougher than the villain by having a lot of minions around, or adding environmental effects the heroes can turn off, or giving the heroes specifically tuned tools to beat the villain. The first two might not work so well here; Treerazer is already 5 levels higher than the heroes will be, so minions need to be in their own encounters beforehand. Environmental effects to make the combat more stacked against the heroes could be problematic, too.

That leaves the last choice. There are a couple of good ways to prepare the heroes for their fight against this tough foe, and I plan to use these three:

* Environmental Advantages. The heroes are going to be able to turn the environment against Treerazer somehow. He thrives on corruption, so the heroes can actively attempt to reduce the corruption and "cleanse" the area around Treerazer a bit beforehand. This might be its own encounter, such as one with 3 terotricuses. The cleanliness will hurt Treerazer somehow, perhaps by shutting off his regeneration or his Defoliation ability. 

* Foreknowledge. The heroes will know beforehand when their encounter with Treerazer will occur. A really tough climactic villain shouldn't surprise the heroes or catch them unawares or unprepared. They should also meet NPCs who can alert them to some of Treerazer's abilities, particularly his aura of corruption.

* Equipment. I plan to seed magic items in this last adventure that are specifically useful in the fight against Treerazer, and these can be really off-the-wall powerful. For example, a +3 major resilient greater fortification orichalcum full plate will help Treerazer's Staggering Strike less likely to occur. A variant of the sky hammer weapon (one that does electricity damage rather than fire damage when it crits and allows the struck creature no save) gets past some of Treerazer's many resistances. A supreme sturdy shield with a hardness of 30 rather than 20 against slashing attacks makes its bearer more durable when going toe-to-toe with Treerazer. And so on.  

All that said, here are the encounters I'm planning:

* Three terotricuses, to "cleanse" some of Treerazer's corruption before the fight. (Moderate)
* Two tarn linnorms that serve as his personal bodyguards. (Moderate)
* Two elite guthallaths that relentlessly patrol the area around his blighted grove. (Moderate)
* Five banshees who are the souls of those who Treerazer most recently tormented. (Moderate)
* Treerazer himself! (Extreme)