Referenced in Atop the Valley’s Soul and The Falling Silk, two of the books in Lowls' footlocker.
A bustling trading port and one of the largest cities in the Dreamlands. A grim city of basalt and one of the Dreamlands’ most notorious havens for vice. Location of the vice den Xuzu.
The crew of blue-skinned human mercenaries that fought alongside Captain Vadrack on the Bloodwind in Chapter 119 were identified as being from Dylath-Leen (as was Ebenezer Anthony Addle).
In Chapter 125, Dora recalled some more information about Dylath-Leen:
The history of Dylath-Leen is one of complete chaos inside a firm structural stability. And the Story of the city is one of the Game.
Dylath-Leen is a massive, crime-ridden metropolis overrun by a sprawling web of politics and bureaucracy and business, and underrun by a sprawling web of crime lords and gangs and seedy enterprises. You can buy, sell, experience, lose, find, or get pretty much anything or anyone you could imagine there. You could strike it rich or end up dying as a prisoner in a torture slavery ring. You could hobnob in the halls of power one day and bleed out in the gutter the next. What makes the place chaotic is that every politician or courtier or bureaucrat or mobster or hustler is constantly scheming and making moves and toppling, or being toppled, and the cycle goes on endlessly. And that’s what’s stable about it: the Game is always on, turf is always changing, kingpins rise and fall, and the story cycles on without there ever being a Mass Change Event. The chaos is the stability.
This is very different from, for example, Celephaïs, where fixtures like Viscount Brellin are seemingly eternal. Maybe he’s got a new Beloved this time you show up. Maybe his party is tomorrow instead of today, but he’s there. And it’s that way with a lot of the big names in Celephaïs. Not in Dylath-Leen. So, while there would certainly be Names to Know in Dylath-Leen at any particular moment of its story, those names may be gone (or information about them may be irrelevant) at the next moment of its story. Everything changes, except the Game.
The reason a name like Quaveandra is “sticky” is because she’s a fixture from the outside. She’s an ambassador from a not-actually-publicly-known Abyssal court to the city, and while things change around her piece of the City’s Story, the Story that she’s an Ambassador to the City seems stable enough that it persists. Or has, for a long time. And maybe that’s why her name caught Thema’s eye in the first place.
In Chapter 129, the party made a brief visit to Dylath-Leen, materializing on a dream reflection of the Sellen Starling long enough to recover Vik’s lost journal.
In Chapter 142, the party made a second trip to Dylath-Leen, on their quest for the Night Hag Ambassador's Heartstone.
In Chapter 143, they explored the drug den Xuzu, met Katarina, and located Quaveandra.
In Chapter 144, the party did some sightseeing in Dylath-Leen and spent the night in Katarina’s high-rise apartment.
First Reference: Chapter 90
Other Notable References: Chapter 101, Chapter 118, Chapter 119, Chapter 125, Chapter 129, Chapter 142, Chapter 143, Chapter 144, Chapter 153