Thaxll'ssillyia

Thaxll'ssillyia is a shadow dragon serving the Shade Lord. He can be found in the penultimate room of the ruined temple of Amaunator.
==Gameplay==
Upon descending the staircase from the level above, your party will enter a cathedral-like open area. During daylight hours, dim light penetrates the dark interior from windows higher up on the walls. The stink of rotting flesh and decay assails your nostrils. A dormant hulking beast is visible within, with great folded leathery wings astride its armored body. There are barely discernable signs of life, such as rhythmic deep breathing. Its eyes appear slitted and half-closed. The great tail from the beast is curled protectively around a pile of bones, golden coins and other valuables. Perhaps this black and grey scaled dragon is in some kind of slumber? If you have the Shadow Dragon Wardstone in your possession, the beast doesn't react to your presence. 
The wardstone will prevent the dragon from being aware of your existence, until some kind of overt action on your part takes place - including speaking to or touching the dragon. Otherwise, it remains still. You do not need to arouse the dragon for any quest completion purpose, and you can safely ignore it. If you wish to claim its treasure hoard or destroy the fell beast then you may do so by announcing yourself by speaking to it, or just attack it with a huge tactical advantage. It is up to you.
If you decide to take on the dragon, get its attention by speaking with it, or attacking it in some manner. It will spring to action with a roar of dialogue in the common tongue, and then engage in battle (assuming it survived some kind of initial surprise attack or spell barrage). 
The dragon has several innate abilities and innate spells it can muster to defend itself and harm you. These abilities and spells can't be interrupted or disrupted by damage. Expect the beast to immediately protect itself with Stoneskin (10 skins) and then launch a level 23 Remove Magic upon the closest enemy. Anyone in melee range may also be attacked by its piercing claws. It can get at least 3 strikes per round at a target.
Shortly thereafter, the dragon will radiate an aura of Dragon Fear in a circle around itself. Those within a certain distance and not immune to Panic effects must make a saving throw to negate this, with a penalty, or they will flee and be uncontrollable (possibly involuntarily wetting their codpiece). 
This is followed by a Shadow Dragon Breath blast upon an opponent closest to the dragon, and then several seconds later, a Wing Buffet. These innate abilities will continue to periodically be unleashed every few rounds (three) - Dragon Fear aura, breath attack and Wing buffet. In between these, the dragon will continue to try and damage the nearest opponent with claw attacks. 
If the battle rages for a few more rounds, and the beast is still functional, it will begin to auto-cast some innate spells, such as Chaos, Greater Malison and 35% chance of a Chromatic Orb. Additionally, if the dragon's melee opponent is protected so that the creature's melee attack is "weapon ineffective", it may reciprocate and protect itself with Protection From Magical Weapons. All of the dragon's innate spells are inexhaustible, and the only limitation is the time delay between their uses. In other words, the beast will not "run out" of spells or innate abilities.
Thaxll'ssillyia has no innate weapon immunities, meaning even normal, unenchanted weapons can hurt it. Switching to normal weapons is one way to hurt it when it casts Protection From Magical Weapons. The player still has to negate its Stoneskin. Breach can negate both.
==Strategy==
This might be the first dragon faced by the party in the saga. It is one of the more dangerous enemies in the early SoA game, especially if the party decides to face it as soon as Chapter II. As usual, proper preparation is the key to winning this battle with minimal strain.
Party members that will be close to the dragon, especially in melee range - will need protection from Level drain. Perhaps a party cleric could cast Negative Plane Protection. If the party has an item that provided this protection such as the Amulet of Power, that would be optimal. A Berserker or Barbarian kit ability can provide protection for a limited time. Unprotected party members in range to the dragon are at high risk. 
Protection from fear effects, like Panic would be prudent for those close by. A Resist Fear spell will do the trick. If that isn't available, then boosting saving throws vs. spell would be another method to mitigate the chances of being frightened and uncontrollable.
Stoneskin would be useful to be able to engage in melee with the dragon, as it hits often and for a considerable quantity of damage. A means to heal the damage is also needed, if the skins are consumed. Mirror Image is also a good defense for a limited time. Expect to be damaged while in melee, and the longer it goes on, the more likely healing will required.
Be prepared for being knocked backwards by the Wing buffeting force. It is hard to resist, especially in unmodded games and early in the saga. You should have a plan for what to do if a single or multiple party members are blown backwards at once. If the dragon has no one to occupy its attention close by, it may advance to another party member (that may be unsuited to go toe to claw with a dragon).
The use of summoned creatures may be a great help. Let those creatures occupy the beast, while the party cast spells or fires missiles from a distance.
Spread out your party so that area of effect spells and attacks can't get multiple members in each use. Keep the dragon busy with at least one party member or summoned creature and overwhelm it with ranged attacks and spells.
A party member could polymorph into a Mustard Jelly via spell or using the Cloak of the Sewers. The form is invulnerable to the dragon's claw attacks. That may be a viable option to increase staying power and get close to the dragon while others deal the damage. If soloing, then this would be good method to eventually defeat the beast. 
==Note==
*The dragon will see through invisibility, sanctuary and stealth as if they were not there. Backstabbing does not affect the dragon either.
*While carrying the Shadow Dragon Wardstone, it's – oddly enough – possible to pickpocket the Shadow Dragon Scales from Thaxll'ssillyia, as well as the Crom Faeyr Scroll and his various gems.
==Gallery==
ShadowDragon.png|Original BG2 image
==Mod content==
:Portraits from Portraits Portraits Everywhere
SHADRA01.jpg|thumb|Thaxll'ssillyia the Shadow Dragon, 
Sword Coast Stratagems revises Thaxll'ssillyia in many ways. Especially if you install the "Smarter Dragons" component (which is responsive to the game difficulty selection). His SCS AI improves targeting and recognition of opponent's protections, which means he will fight smarter and not waste attacks on someone he cannot hit or damage. It will also influence his tactical options and attack methods. First, some mention of the dragon's stats and abilities. In most cases, all of the unmodded ones are still applicable:
*Thaxll'ssillyia is a 23 Hit Dice dragon (casts spells at level 23)
*480 Hit Points (depends on game difficulty setting)
*3 Attacks per round 
Immunities in addition to the unmodded dragon version:
*100% Cold resistance
*Intelligence Modification (feeblemindedness will work, but not Mind Flayer devour brain)
*Blindness
*Imprisonment
*Slay
*Kill target
*Otiluke's Resilient Sphere
*Critical hit averted due to HELMNOAN.ITM
*Most Cold based spells (Ice Storm, Cone of Cold etc.)
As stated in the article above, Thaxll'ssillyia has access to several innate Dragon abilities. They are uninterruptible. A little bit more on what SCS does with the following:
*Shadow Dragon Breath (SPIN893): SCS does not change the on hit effects, but it does change the breath weapon to have no "Secondary Type" classification. It does use it intelligently, and at some point, may use it more frequently if the battle lasts a while. It typically will attempt to blast a target right after it employs a Remove Magic (of which it can do twice).
*Dragon Fear (SPIN895): Moderately sized 16 ft radius aura centered on the dragon, ticks about every three rounds. No MR resistance or spell protections apply. Save vs. Spell at -4 or be affected by Panic. Fear protection can prevent, or remove the panic effects, but dispel magic will not remove it. Duration 1 turn.
*Wing Buffet (SPIN695): as described in main article. It is a moderately sized 16 ft area of effect around the dragon. Victims within are knocked back 30 feet away from the source (no save), then go Unconscious for 3 seconds (save vs. spell with -10 penalty to negate) and are hurt for 1d8 +12 crushing damage (no save). If you place a cloud spell on or near the dragon, at least one that is recognized by his AI, he will employ a buffet to clear the air. This means that cloudkill or death fog won't be a winning option.
*Protection From Magical Weapons (SPIN686): As per the Wizard spell
*Stoneskin (SPIN694): As per the Wizard spell with 10 skins applied.
Spells: Thaxll'ssillyia is scripted to use the following spells, as determined by the AI's need, and your party's protections: Chromatic Orb, Remove Magic, Greater Malison, Breach , Death Spell, Chaos. 
SCS looks for the party preparing for battle, simulating that Thaxll'ssillyia would be alerted of an imminent hostile action. Any trap setting, creature or demon summoning or certain spells will possibly trigger a hostile reaction. I won't spoil the spells it looks for, but it includes many of the favorite party-wide buffs from wizards and clerics such as Haste and Draw upon Holy Might, Protection from Fire and others. You just can't buff with certain spells in the presence of the dragon without triggering a response. Forget setting a trap near the dragon or within visual range. If you summon an elemental, or some cannon fodder from the wand of summoning of any kind, he will become hostile. Buffing and summoning must occur out of sight from the dragon. If a summoned creature moves into visual range that will also trigger a hostile reaction.
One warning for a party facing the dragon. SCS AI can recognize members that are protected from level drain. It sees Blackguards, Undead Hunter, Enrage ability, Negative Plane Protection, and similar. It will try and aim a breath weapon attack at someone who has no level drain protection. Keep those individuals out of the dragon's sight range (which is about 30 feet, at least as good as a party member.) If a breath attack is launched at a member, they may try to run away as the projectile heads toward them and out run it, but that is difficult (but not impossible). A good length of distance is needed for that tactic to work, and Haste or Speed boots.
On "Insane" difficulty, the dragon has better saving throws (probably will not fail any, unless a Greater Malison is used, and then, rarely). Regains use of Shadow Dragon Breath quicker than the unmodded game. Could potentially by percentage, have a 50% chance each round to blast with it. 
For the greatest challenge, speak with the dragon in order to hear his threats and boasts, and only then engage in combat. Do not attack unprovoked with the wardstone in your inventory for a fairer battle experience. 
With the installation of the Spell Revisions mod, some of the dragon's arcane memorized spells will be the SR version. The innate abilities mostly are not revised except for the dragon breath. With SCS or SR, the Spell Shield bug behavior is fixed, so the spell works as it should. It no longer interacts at all with the Dragon's breath attack. In the unmodded game the Spell Shield bug trivializes the dragon's breath weapon, which is most probably an unintended coding omission.
==Mod gallery==
THAX1.png|Shadow Dragon awakens and roars out threatening words to PC.
THAX2.png|Dragon attacks. First with Dragon Fear, save made. Shadow Dragon Breath next. PC blinded, Negative Plane Protection prevents Level drain.
== Achievements ==
===Shadow Dragon Slayer===
Slew the shadow dragon, Thaxll'ssillyia.
==External links==
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==References==
Category:Shadow dragons
Category:Protected from poison