Chauncy and Edgar are Demons from() from Fratz.
As an after-effect of The Breach, holes opened up() sending them through() the River of Fire to the Basement where they became measures of troublesomeness() and sturdiness().
While they are both strong, Chauncy is more powerful, but both can be harmed() by cold-forged iron. They can communicate with each other, but only Edgar has learned to communicate with other non-Demons(). (Chauncy hasn't even learned to hear, but he can gum and grok().)
Edgar and Chauncy discussed taking over() the Mansion but were imprisoned() in a bottle of "penalty wine" by Ghasts from the Basement Council, but escaped() during the Endless Day.
When the Council discussed the Elevator fire the council members were concerned about the fire damaging the bottle() and allowing Chauncy and Edgar to escape. Many other basement dwellers were also concerned() with a release, including Ploot as the pair had visited() the Hot Zone before being bottled.
The Operator sends an enchanted stream of fire() that passes through the bucket brigade putting out the Elevator fire and reaches() Rubrak. The tool held by Rubrak flys() into the bottle of penalty wine and knocks off a chip.
From the chip the wine bottle develops a leak(). After study() and discussion(), Chauncy takes() Edgar's horn and enlarge() the hole and the pair escape. The fracturing of the bottle was widely noticed() and caused aggravation().
Chauncy and Edgar resume() causing trouble, but with less enthusiasm(). Earlier that day Sylvester and Rosemary walked by the penalty wine bottle and Chauncy and Edgar recognized() Rosemary (both specifically, and as an interesting subject), and they now thought they could learn something new from disassembling() Rosemary.
While the mechanism is not described, the pair were directed() toward Rosemary by The Operator.
They meet() Rosemary in Izchak's shop. When Rosemary hears they want to disassemble both her and Sylvester to study the differences() she attacks Edgar with the Can-Opener and explains they the Wide World is real() and they have been hurting beings.
Rosemary tells them to leave and learn to interact with others(). When Edgar says the can't leave because of the Barrier Sylvester suggests they ask Myrrh to send them away. Chauncy requests Rosemary hit him() with the Can-Opener so he can understand the experience.
When they meet() Myrrh they ask to be sent to a new place, not home, because they have "become accustomed to possessing names"(). She leads them() to a Panegate and sends them away().