Only women are born ymbrynes, and thank heaven for that! Males lack the seriousness of temperament required of persons with such grave responsibilities. We ymbrynes must scour the countryside for young peculiars in need, steer clear of those who would do us harm, and keep our wards fed, clothed, hidden, and steeped in the lore of our people. And as if that weren't enough, we must also ensure that our loops reset each day like clockwork.

–Miss Peregrine, Miss Peregrine's Home for Peculiar Children

The shape-shifting matriarchs of peculiardom. They can change into birds at will, manipulate time, and are charged with the protection of peculiar children. In the Old Peculiar language, the word ymbryne (pronounced imm-brinn) means "revolution" or "circuit."