Book 1 Chapter 3 Edit
Layla Brimstone was first seen listening to the public ravings of Number 1, the blue devil that 82 accosted. (KSBD 3-51) Shortly afterward, she was the first in the crowd to challenge Eris-Lo Kai's claim to the Key, firing a pistol into the air and beginning an intense standoff amongst the warriors present at the scene. (KSBD 3-52)
Book 1 Chapter 4 Edit
Book 2 Chapter 5 Edit
She appears with the other pursuers after Allison's key at Mottom's palace. Wielder of Names 5-101
Book 2 Chapter 6 Edit
She appears in the War of the Teacups. Wielder of Names 6-103 to 6-104 (War of the Teacups)
Layla appears to be human, albeit an exceptionally pale one. She has short red hair, although it's not often visible under her enormous, broad-brimmed hat. Beneath her longcoat, she wears armor, strapped with a broad variety of guns and ammunition. She seems to be a Vane Black homage or expy.
Although she has not displayed any particular usage of the Art, it can be safely assumed that in addition to her marksmanship, Layla wields considerable magic to complement her weaponry. She can employ one of her rifles to fly in similar fashion to how a traditional witch uses her broom.