SCS Siege of Ust Natha in Legacy of Bhaal Mode

semiticgoddess · April 2017

I promised to post an in-depth analysis of SCS' Siege of Ust Natha, which I managed to complete in Legacy of Bhaal mode with minimal metagaming (I knew very little about the fight before I started) and no reloads besides some crashes and bug-related problems. I already discussed my own experience in depth, including the bugs, in 12 lengthy comments, but here I want to discuss the challenge in more general terms. Note that my findings here only apply to Legacy of Bhaal mode; other difficulty levels will play very differently. You can find all 12 posts here:

I used several exploits/tricks/glitches in my run, and exploits are normal for this fight, as it is not supposed to be beatable using normal means...

DavidW said:

It's not exactly designed to be impossible; it's more that it's not designed to be possible (if that distinction makes sense). It's intentionally way more enemies than is reasonable at that level.

...but I wanted to explain how the player can win the fight without using those exploits. These are the tricks that I used:

1. The Wand of Lightning trick. If you have a character using the Wand of Lightning's six charges on him or herself before using an on-self spell or item, you can multiply the effects by 6. Thus, you can cast six Sunfire spells at once, six Wishes at once, or drink six potions at once while only expending one. In my install, Item Revisions nerfed it to only 3 targets.
2. The Bigby's Crushing Hand+Spell Trap trick, which @Demivrgvs plans on closing in the next version of Spell Revisions. By having one mage cast Bigby's Crushing Hand on another mage and then having the second mage cast Spell Trap, the first mage can use a single level 9 spell slot to restore multiple level 9 spell slots for the second mage. This is very time-consuming and leaves both mages vulnerable. It may or may not be possible without Spell Revisions.
3. A bug allowed the Hardiness spell from Wish to stack on everyone except for the caster.
4. Use Any Item allowed me to equip an Earth Elemental Token from SCS' Improved Shapeshifting component, which, combined with several items from Item Revisions, boosted one character's physical damage resistance to 90% without needing any buffs.
5. The Seducer kit. An early version of the kit could charm groups of enemies despite their MR, spell protections, and immunities, at the cost of preventing the Seducer from attacking and imposing AC and movement rate penalties.
6. A bug of some sort allowed me to summon multiple Devas and Planetars.
7. My party was imported and had 1.5 million XP at the beginning of the game.
8. A bug allowed my Simulacrum clones to use HLAs such as Dragon's Breath. In my install, they were supposed to be usable only by the original caster.

If you wanted to avoid using these tricks, you could replicate them through normal means:

1. Having a second sorcerer in the party and/or using Project Image to continue casting Wish would ensure successful Wish-resting without the Wand of Lightning trick.
2. Having more than one mage would make the Bigby's Crushing Hand+Spell Trap trick unnecessary. Also, a level 35 sorcerer can gain infinite spells using a Simulacrum clone, as a level 35 mage will get a level 18 Simulacrum that can therefore cast level 9 spells and restore Wish spells on the caster using Spell Trap.
3 and 4. I will discuss alternative means of tanking below.
5. The current version of the Seducer kit uses an area-effect Feeblemind spell rather than a charm effect.
6. Project Image clones can summon multiple celestials, and there are mods that remove summoning cap on both normal creatures and celestials. Also, having more fighter levels in the party (no one in my party had any fighter levels) would obviate the need for extra celestials.
7. My party never went past the first level of Watcher's Keep, which could have granted far more XP than I had imported.
8. With the right SCS install, HLAs like Dragon's Breath are level 9 spells and high-level Simulacrums can therefore use them normally.

I had 5 characters at about 9 million XP apiece. Having 6 characters at 6 million XP would be a reasonable minimum before tackling the Siege of Ust Natha in LoB mode. There are four primary threats that you have to deal with.

Threat 1: Duration

The Siege of Ust Natha is an extremely lengthy fight. Buffing spells will run out long before the fight is over, so parties that rely heavily on short-term buffs will find themselves extremely vulnerable in the late stages of the fight.

The party needs to have sustainable damage output and sustainable defenses. PFMW will not be enough to keep the party alive, and emptying your spellbook via Improved Alacrity will only give you a temporary reprieve from the enemies. The party either needs to be extremely low-maintenance--that is, it does not require many spell slots to function at full capacity--or it needs to be able to restore its spell slots via Wish or Limited Wish. If you have two mages who can cast Wish, you can expect to get Wish-rests every few rounds, and you can be fairly sure you won't run out of spells midway through the siege. If you have one sorcerer who is level 35 or higher, you can use a Simulacrum clone and Spell Trap to restore your spell slots, guaranteeing a supply of infinite spells, but you won't be able to Wish-rest so often.

Threat 2: Damage

Mid-level drow fighters and clerics spawn every few rounds for the duration of the fight. They are equipped with +3 weapons and have -4 to -8 AC, 72+ magic resistance, and 300+ HP, along with +5 to saving throws, +1 to APR, and about 20 effective levels thanks to LoB bonuses. If you have Item Revisions installed, they will also have 15-25% physical damage resistance and +2 to hit and damage. Put together, the enemy has extremely high APR and is extremely difficult to kill. If the player does not kill the drow fast enough, they will build up and overwhelm the party with sheer numbers.

The party needs to be able to get past the enemy's massive MR and low AC. Skull Trap and Horrid Wilting spells will help, but it won't be enough, as the enemies will resist most of the damage. The party can get past the enemy's defenses if it can achieve high APR and low THAC0 without needing lots of buffs to maintain it. This means fighter levels will be crucial in thinning the enemy herd and minimizing the amount of pressure on your party.

There is a convenient choke point in the doorway to the northwest room where the Lesser Demon Lord first appeared. I used that room as a sanctuary, but you can also hole up in the treasury chamber, where the dragon eggs were hidden, or even form a wall of meat shields in the southeast hallway. All of these points will allow you to avoid getting surrounded and keep most of the enemies away from you. This decreases the pressure on your defenses, as most of the enemies use melee weapons.

Threat 3: Mages

Higher-level spellcasters will spawn less often during the fight, but they will use debuffing spells that could easily leave the party vulnerable. Bear in mind that LoB enemies get +12 levels apiece, so their Remove Magic spells will be far more effective than you might suspect. The mages will, of course, arrive fully buffed, and it will be difficult to stop them from dispelling your defenses.

The party either needs to be able to ward off enemy debuffers by re-casting SI: Abjuration or Dispelling Screen and the like, or it needs to be able to shut down enemy spellcasting without using up valuable rounds or spell slots. You can take down a mage in a single round if you use Secret Word, Pierce Magic, and two Breach spells in a row to break through the mage's PFMW pre-buff and PFMW Contingency, but that requires four party members to work in concert--which may not even be an option if one of the four needs to drink a potion or shore up their defenses.

Threat 4: Demons

Late in the fight, demons will enter the fray. In my case, I saw two Nabassus, two Glabrezus, and two Balors arrived on the field more or less simultaneously. All of them have instant-casting Remove Magic spells that cannot be stopped by spell failure, and the Balor will be casting the spell at well over level 30. If you left too many drow on the screen when the demons arrive, losing your defenses could prove fatal.

Party Options:

At root, the party's strategy needs to revolve around the ability to resist melee weapons, Remove Magic, and Breach. Most of the threat comes from swords and flails; the enemy does not rely heavily on spell damage or disablers. Unlike most high-difficulty fights in BG2, the Siege of Ust Natha revolves around attack rolls and AC, not saving throws and MR.

Think of the Siege of Ust Natha as if it were a major fight in Icewind Dale. The only difference, strategically speaking, is the existence of Remove Magic and Breach. So your party needs to be able to do several things:

1. Deal lots of nonmagical damage over a long period of time.
2. Maintain strong defenses over a long period of time.
3. Either shrug off Remove Magic and Breach, or operate at full capacity without using buffs that can be Breached or dispelled in the first place.

Utility characters like thieves will not be much use in this fight; it simply isn't suited to them. There are six different classes who are especially suited to this kind of challenge:

1. Fighter/Druid
2. Dwarven Defender
3. Barbarian
4. Bard
5. Sorcerer
6. Wild Mage
7. Fighter/Mage

The Fighter/Druid:

Fighter/Druids have one distinct advantage here: the ability to use Hardiness while in Earth Elemental form. Whether you're using vanilla shapeshifting or SCS' Improved Shapeshifting component, Earth Elemental form should grant 50% resistance to all forms of physical damage. A Fighter/Druid at 6 million XP can cast Hardiness about 6 times, so he or she would have undispellable 90% damage resistance for 60 rounds. This would not be enough to last the whole battle, but Wish-resting and Armor of Faith could keep the Fighter/Druid highly resistant for basically the entire battle. If you have Item Revisions installed, you can also stack the damage resistances from IR armors with an Earth Elemental Token, boosting your damage resistance to 100%.

On top of that, the Fighter/Druid will have undispellable 3 attacks per round at low THAC0 and high damage, which will help thin the enemy herd.

Fighter/Druids have never had the saving throws and anti-mage capabilities as other classes, but this weakness is largely irrelevant in the Siege of Ust Natha, in which the primary threat is weapon damage. Fighter/Druids will, however, have no defense whatsoever against Remove Magic, so Ironskins and similar buffs will not last long on them.

Characters with Use Any Item can also use an Earth Elemental Token.

The Dwarven Defender:

With 20% innate damage resistance, another 20% from the Defender of Easthaven, and 50% damage resistance from Defensive Stance, the Dwarven Defender will be able to maintain 90% damage resistance for almost the entire battle, just like the Fighter/Druid. For the purposes of this fight, their function is identical and they are about equally good at it.

The Barbarian:

Barbarians will also have 20% innate resistance and another 20% from the Defender of Easthaven, but they will have to use Hardiness instead of Defensive Stance, for a total of 80% damage resistance. Barbarians have higher STR and immunities than Dwarven Defenders, but they will not be nearly as effective, as 80% damage resistance means the Barbarian takes twice as much damage as a Dwarven Defender or Fighter/Druid (unless you have Item Revisions, in which case full plate mail or the Orc Leather +3 will grant 100% resistance to all three of them). Regardless, a Barbarian should be capable of withstanding enemy pressure for the duration of the fight despite Remove Magic and Breach, provided he or she has a lot of healing potions.

The Bard:

Bard songs no longer stack in EE, but the Improved Bard Song still grants +4 to hit, damage, and AC to all party members, which means a bard can substantially even the odds. Bard songs cannot be dispelled, do not require spell slots, and do not require the bard to use up his or her aura, so this is essentially a constant, guaranteed buff as long as the bard is alive.

However, bards have no damage resistance, at least not nearly enough to keep them alive in this fight. Instead, they need to use their mage spells to survive. Such defenses are dispellable, but a bard can easily hit level 50 by the time the party reaches the Underdark, which means a bard's defenses should be nearly immune to Remove Magic. Only Breach can render the bard vulnerable, so Spell Shield would be a staple of the bard's defenses.

The bard should either stay out of melee combat or ideally achieve extremely low AC. The Improved Bard Song gives +10 AC to the bard itself, so it's entirely possible for a bard's Mirror Images and Stoneskins to keep them safe.

But if the bard does get Breached or somehow dispelled, he or she will need a quick escape, as they will not have the resistances to survive long on their own.

The Sorcerer:

Sorcerers themselves will not usually be spectacular tanks in this fight. PFMW will make them totally immune to the enemy's weapons, but it only lasts 4 rounds. However, the sorcerer is extremely adept at Wish-resting and can restore the party's HLAs. Wish can also reduce the enemy's MR to 40, grant Hardiness to the party, grant Improved Haste to the party, heal everyone, or impose 100 intoxication on everyone in the area, which amounts to a crippling -12 luck penalty. Depending on your install, Slow Poison, Neutralize Poison, Greater Restoration, and Elixirs of Health can cure intoxication, and Wish intoxication can be blocked by MGOI or dispelled, so you can keep your party sober while the enemy suffers -12 to every attack and damage roll due to intoxication.

Being able to summon Planetars also helps even the odds, and if you're not worried about failing to get a Wish-rest, then your sorcerer can use Dragon's Breath on the drow, as it will bypass their magic resistance. Plus, Wish intoxication will cause any drunken enemies to suffer full damage from Dragon's Breath (100 on a successful save, 200 on a failed save).

The Wild Mage:

Wild Mages have the same function as sorcerers: Wish-resting first and foremost, but also Summon (Fallen) Planetar and Dragon's Breath. Wild Mages can use Nahal's Reckless Dweomer to cast Limited Wish to restore 4 Nahal's Reckless Dweomer spells, which means they are less likely to run out of level 9 spell slots before they get a Wish-rest, but the wild surges, as always, can make things worse. More importantly, getting a Wish scroll for your Wild Mage by the time you reach the Underdark is very difficult.

The Fighter/Mage:

Fighter/Mages have neither the Wish-resting ability of sorcerers or Wild Mages, the durability of Fighter/Druids, Dwarven Defenders, or Barbarians, or the bard's resistance to Remove Magic. They are conventionally powerful as always, with the caveat that they need to be especially careful if they want to hold onto their buffs.

The Invisibility Option:

This is untested, but theoretically, you could win the entire fight by relying on a Shadowdancer's Hide in Plain Sight or the Staff of the Magi, possibly combined with Non-Detection. The demons can easily see through your invisibility, but if you voluntarily let the drow crowd the entire map and surround you, the demons will not actually be able to reach you, allowing you to very slowly kill them with missile weapons before turning invisible again. Once the demons were gone, you could then kill the drow without fear of retribution.

The process would be extremely lengthy and would try any player's patience, but this should allow a solo character to win the Siege of Ust Natha.

[Deleted User] · April 2017

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comebackhome · April 2017

Will refer to this if I become stuck during my current LoB SCS run seems fairly indepth - ty