"Cruels and Hags and Incubuses, Wraiths, Horrors, Efreets, Sprites, Orknies, Wooses, and Ettins. In fact here were all those who were on the witch's side and whom the Wolf had summoned at her command."
―Chapter 14 [src]

Cruels were evil things that served the White Witch during her reign over Narnia.

They were present at the Stone Table, during Aslan's sacrifice, and fought in the White Witch's Army at the First Battle of Beruna.

Nothing else is known about them, not even their appearance, except that apparently they were so horrible to look at that they could not be described.

"...other creatures whom I won't describe because if I did the grown-ups would probably not let you read this book."
―C.S.Lewis (Chapter 14) [src]