- "Ylla? Where the hell is Ylla?"
- ―Ivan on learning of his new assignment/exile[src]
The planet had extensive oceans with water that gave people rashes and large sea monsters that ate people despite the fact that people were highly toxic to them. It was not heavily populated, and it had no large cities - the planetary capital's population was about 1/20th that of Vorbarr Sultana. Midwinter in the capital city was rainy and cold. The plants tended to be a blue-green color.
Following the events of Captain Vorpatril's Alliance, Ivan Vorpatril along with his wife Tej, was appointed senior military attaché to Ylla, presumably as a combination extended honeymoon and exile.
- "Ylla" is a reference to a Martian woman from The Martian Chronicles.