The Attack at Nightfall

The undead from Castle Redcliffe have begun the attack upon Redcliffe Village. The Warden and their companions stand with the village's defenders. This is an optional part of the Arl of Redcliffe quest (only available if A Village Under Siege was completed).

Walkthrough
The quest consists of two phases:

1. Defense of the Windmill: The Warden's party starts at the windmill along with Ser Perth and his knights, plus Dwyn (with his pair of thugs) and/or Berwick, if you have recruited either of them. If the Warden suggested to Ser Perth that the oil barrels in the General Store might be useful, they will be added to the barricade and set on fire (if Zevran is in the party, he will issue a wise warning about this). The knights (and anyone else not managed appropriately) may run into the fire to attack the walking corpses. Though the fire doesn't harm defenders at Casual difficulty, it is not advised to let anyone (living) near it at higher settings.

2. Defense of the Chantry: After the undead at the windmill have been defeated, a militiaman will run up from the barricades in the centre of the village to report that more undead have crossed the lake and are attacking the Village Chantry's defenders. The Warden's party must hurry there and help fend off several more waves of attackers. Murdock, Tomas, and the rest of the militia will be there, plus Lloyd if he was recruited.

Note to XP opportunists and the malicious: All of the village's defenders can be slain by repeated applications of AOE spells (Shock, Fireball, Blizzard, etc.) and such deaths apparently yield XP. Also, if Owen was convinced to do the militia's repairs, every fallen militiaman will drop a fullStudded Leather Armor Set. It is possible to earn up to 18 if done relatively late/at a very high level.

Tactics
If handled well, this can be an easy battle; just take care to monitor your companions' Tactics Slots. Some other tips that will help you succeed:

First phase
If the oil barrels are used to set the barricade on fire:
 * Earthquake, set on and behind the barricade as each wave of undead approaches. This works even better if the Warden's entire party keeps ranged attack options, and especially well if the oil barrels are used.
 * You can keep overeager knights from running into the fire by having a tank stand as far from the knights and as close to the barricade as possible, taunting and threatening. Have other companions do the same, or stand close by firing missiles to catch more attention. This should draw the undead through the fire and away from the knights.
 * Make good use of AOE on the undead before they reach your group - particularly spells with knockdown, slowing or stunning effects. Note that on Easy (and Normal on the console) there is no friendly fire damage, although most freeze/stun effects do still affect allies. Suggestions include Fireball, Captivating Song, Mind Blast, and Paralysis Explosion. It is worth mentioning that the undead are especially vulnerable to fire but are immune to nature and have a heightened resistance to cold.

Second phase

 * Scattershot is especially useful here, as enemies approach from multiple directions.
 * Focus attacks on any undead that are attacking archers, mages, Lloyd, and generic militiamen (or the most wounded one). Heal these targets first as well, since Murdock and Tomas have relatively more armor and health.
 * If Lloyd was convinced to join the battle, keep an especially close eye on him, as he is prone to charging away from the group and doesn't have much in the way of armor.
 * If you have Shale with Stone Aura, put it just in front of the fire (with the chantry opposite it) and activate the aura. This can be nicely augmented by Force Field.
 * If the militia is wiped out, pull the undead towards the windmill so that the knights can help you (if the knights weren't wiped out during the first phase).

General

 * For lower-level characters lacking higher-tier abilities but still wishing to keep all (or the majority) of the NPC allies alive, a good tactic is to set up a party with predominantly tanking characters, and set tactics to emphasize knockdown and stunning moves (Shield Bash, Pommel Strike, Overpower, Shield Pummel) on 'nearest visible' enemies. This is most useful during the 2nd phase.
 * Set the Behavior of companions to Defensive or Cautious, or manage their targets closely. Otherwise they can end up wading into the fire to attack the undead in the first phase, or moving too far from the chantry in the second phase, making the militia less effective (against enemies at a greater distance) and more vulnerable (to attackers coming from wherever the wayward character isn't).
 * Lure traps (set only after the battle starts, sadly) for getting attackers away from where they aren't wanted (drawing knights into fire, mobbing Lloyd when he charges out into the open, etc.); a reasonable supplemental effort if there aren't enough characters with Taunt.
 * Try to have one mage in the group with Heal - preferably two. Pause combat every so often to monitor everyone's health levels ( or keep Tab held down frequently). Use poultices to keep the Warden and companions up so the spell can be saved for NPCs. Don't forget the Tactics slot "Self: Health < X% = Use: X Poultice" if avoiding micromanagement.
 * Cleansing Aura makes this fight much easier, as it affects all of the defenders. Make sure the caster never runs out of mana, perhaps with a lyrium potion Tactics slot. This offers a very good chance of no fatalities, even at Nightmare difficulty.
 * Don't forget the option of lowering the Difficulty setting before or during the battle.
 * To see whether or not any soldiers have fallen or not, look at the remains; if a corpse has blood, then it is a fallen soldier (from the militia). If there is no blood, then it is a fallen undead.

Bugs
Note: The console command runscript zz_arl_debug can be used to skip the battle in the event that either of the following bugs make it impossible to complete.

Results
A cutscene shows the village offering thanks to the Warden, plus remembering those who died (if any). Then Bann Teagan asks you to meet him at the mill to discuss how to get into the castle.

There is a Doomsayer after the village has been defended successfully. You can intimidate him, kill him, or leave him alone. However, there appears to be no XP. He will reappear, and this time you can also persuade him to shut up.

Rewards
(if Lloyd is recruited and survives.) (if all named NPCs and all of the knights and militiamen survive.)