From A Wiki of Ice and Fire
The Warlocks of Qarth are known to dress in long, beaded robes. They have white, pale skins and pale blue lips, from drinking shade-of-the-evening many times, in pursuit of ever-greater knowledge. The Undying Ones' flesh is ripe violet blue, their nails are so blue they are nearly black, and even the whites of their eyes are blue.
Though legend speaks of the mighty power of the warlocks, they have done little in the past century. Similarly to the Alchemists' Guild of the Seven Kingdoms, the warlocks' power and prestige have waned over the years. Their mighty House of the Undying is long since a grey stone ruin, neither repaired nor expanded upon, often referred to as the 'Palace of Dust'.
|“||A warlock's house is built of bones and lies.||”|
The telling of this saying prompts Daenerys to ask Xaro Xhoan Daxos then why do men lower their voices when they speak of the warlocks of Qarth, adding that all across the east, their power and wisdom are revered. Xaro replies:
|“||Once they were mighty … but now they are as ludicrous as those feeble old soldiers who boast of their prowess long after strength and skill have left them. They read their crumbling scrolls, drink their shade-of-the-evening until their lips turn blue, and hint of dread powers, but they are hollow husks compared to those who went before. Pyat Pree’s gifts will turn to dust in your hands, I warn you.||”|
Even so, the Warlocks are feared and respected throughout the East and many enter the 'Palace of Dust', none leave again.
|“||Pyat Pree has blue lips, and it is truly said that blue lips speak only lies. … Warlocks are bitter creatures who eat dust and drink of shadows. They will give you nought. They have nought to give.||”|
After Daenerys Targaryen’s visit to the House of the Undying and the death of the Undying Ones Xaro Xhoan Daxos tells Dany that Pyat Pree is gathering the surviving warlocks together to work ill on her. She laughs at this news and asks him was it not him who told her warlocks were no more than old soldiers vainly boasting of forgotten deeds and lost powers? Xaro looks troubled and replies:
|“||And so it was, then. But now? I am less certain. It is said that the glass candles are burning in the house of Urrathon Night-Walker, that have not burned in a hundred years. Ghost grass grows in the Garden of Gehane, phantom tortoises have been seen carrying messages between windowless houses on Warlock’s Way, and all the rats in the city are chewing off their tails. The wife of Mathos Mallarawan, who once mocked a warlock’s drab moth-eaten robe, has gone mad and will wear no clothes at all. Even fresh-washed silks make her feel as though a thousand insects were crawling on her skin. And Blind Sybassion the Eater of Eyes can see again, or so his slaves do swear. A man must wonder … These are strange times in Qarth.||”|
Events Involving Warlocks
In an effort to cure Samwell Tarly of his timidity his father Lord Randyll Tarly once brought two warlocks from Qarth with white skin and blue lips to his castle at Horn Hill. The warlocks slaughtered a bull aurochs and made Sam bathe in the hot blood, but it did not make him brave as they’d promised. Randyll Tarly had the warlocks scourged.
Archmaester Marwyn studied with warlocks.
A Clash of Kings
At the beginning of her stay in Qarth Xaro Xhoan Daxos warns Daenerys Targaryen to avoid the warlocks in the city. Eventually, after having been refused by the Pureborn, Daenerys decides that she has no other options available to her other than to seek Pyat Pree and the warlocks. Xaro warns her not to go but she goes anyway. After Daenerys's visit to the House of the Undying and the subsequent death of the Undying Ones, Xaro tells Daenerys that Pyat Pree is gathering the surviving warlocks together to work ill on her.
A Storm of Swords
On the Balerion Daenerys thinks of various threats she faces. She recalls that back in Qarth Pyat Pree has sent a Sorrowful Man after her to avenge the Undying she'd burned in their House of Dust. She remembers that it is said that warlocks never forget a wrong. 
A Feast for Crows
Euron Greyjoy tells his brother Victarion that he had captured four warlocks in a galleas out of Qarth. On board was a cask of shade-of-the-evening along with some cloves and nutmeg and forty bolts of green silk. The four warlocks told him a curious tale which Euron does not elaborate upon. One threatened the corsair so Euron killed the warlock and fed him to the other three.
A Dance with Dragons
|“||Beware men with cold hearts and blue lips.||”|
|“||If a warlock’s spell could kill me, I would be dead by now. I left their palace in ashes.||”|
References and Notes
- ↑ 1.0 1.1 A Clash of Kings, Chapter 27, Daenerys.
- ↑ A Clash of Kings, Chapter 48, Daenerys.
- ↑ A Clash of Kings, Chapter 40, Daenerys.
- ↑ A Storm of Swords, Chapter 8, Daenerys, p 92.
- ↑ A Feast for Crows, Chapter 29, The Reaver.
- ↑ A Dance with Dragons, Chapter 16, Daenerys, page 211.
- ↑ 7.0 7.1 A Dance with Dragons, Chapter 16, Daenerys.