Terciel and Elinor by Garth Nix

Terciel has been plucked from a life of poverty to learn his destiny as Abhorsen-in-Waiting and master of the bells, and of the Dead. Elinor sits behind closed walls, safe from the magical Old Kingdom ... or so she thinks. Soon these two will meet each other, and their destiny. A magical prequel in Garth Nix's masterful Old Kingdom series.
SHORT-LISTED CBCA Book of the Year, Older Readers
SHORT-LISTED Aurealis Awards, Best Young Adult Fiction
SHORT-LISTED Locus Awards, Best Young Adult Fiction
Beware the wind from the North!
In the Old Kingdom, a land of ancient and often terrible magics, eighteen-year-old orphan Terciel learns the art of necromancy from his great-aunt Tizanael. But not to raise the Dead, rather to lay them to rest. He is the Abhorsen-in-Waiting, and Tizanael is the Abhorsen, the latest in a long line of people whose task it is to make sure the Dead do not return to Life.
Across the Wall in Ancelstierre, a steam-age country where magic usually does not work, nineteen-year-old Elinor lives a secluded life, her only friends an old governess and an even older groom who was once a famous circus performer. Her mother is a tyrant, who is feared by all despite her sickness and impending death . . . but perhaps there is even more to fear from that.
Elinor does not know she is deeply connected to the Old Kingdom, nor that magic can sometimes come across the Wall, until a plot by an ancient enemy of the Abhorsens brings Terciel and Tizanael to Ancelstierre. In a single day of fire and death and loss, Elinor finds herself set on a path which will take her into the Old Kingdom, into Terciel's life, and will embroil her in the struggle of the Abhorsens against the Dead who will not stay dead.
'There is no joy like returning to the Old Kingdom.' - LEIGH BARDUGO, New York Times bestselling author of Shadow and Bone and Six of Crows
'[A] series of books by Garth Nix that I'm very into.' - MARGOT ROBBIE