Eventually, while wandering the world map, a Messenger will approach you and announce Defender’s Heart is being attacked by demons. Make sure you’re fully rested, have Grease, and buff up your main character beforehand, because you’ll need it.
Other Pathfinder Wrath of the Righteous Guides:
Note: if you lose the fight, the game won’t end, but your fight for the Wardstone will be much harder now as you’ve lost half your fighters and had your arsenal raided.
Phase I: West Gate / Arsonists
Position all but your main tank and a ranged/melee character behind the Crusaders in front of the tavern, using them as your frontline. The tank and ranged/melee you should position on the high ground where the enemies spawn and have them use ranged attacks whenever any Arsonists are on screen (if you don’t kill them asap, you will lose), and melee when there aren’t. Buff them when you get a chance.
After taking down a bunch of enemies, more will approach the wall and begin to climb the ladders.
Continue with your plan, taking special care to kill the Arsonists as soon as possible, of which there will be more now.
Phase II: Minotaur
The minotaur will approach from the east gate now and attack the Crusaders. The Grease you placed earlier plus Evil Eye – AC will make short work of him in combination with your ranged attacks (from the initial four party members) and the Crusaders.
Phase III: Cleanup
From here you can get aggressive, moving all party members forward as needed to take out the Arsonists, which can still cause you to lose in the blink of an eye if they aren’t dealt with immediately, no matter how well you might be doing at this point. Boneshaker can be a good idea here, taking them all out in one shot each with a little luck.
Post combat you’ll confer with Irabeth and receive 695XP, Bite, and Heavy Flail of Weakness.