Brum earned a reputation among the Ravkan Second Army as a ruthless, innovative witch-hunter, having doubled the ranks of the drüskelle during his tenure and pursued Grisha not just in Ravka, but in other lands and on the sea as well. Fifteen years prior to the events of Six of Crows, Brum built facilities in the old vault of the Ice Court's treasury for experimenting on Grisha, trying to control Grisha to use against other Grisha in battle.
Six of Crows
Nina Zenik recalls meeting Jarl Brum in the hold of a drüskelle ship after she was captured by Matthias on the Wandering Isle. She assumed he had perished at sea during the storm that destroyed the ship.
Nina is horrified to learn Brum is not dead when she finds herself face to face with him at the Ice Court's Royal Palace during Kaz Brekker's mission to rescue Bo Yul-Bayur. Matthias Helvar realizes Brum recognizes Nina and pretends he is still loyal to the drüskelle to gain Brum's trust, rescue Nina, and find Yul-Bayur. Meanwhile, Nina pretends to flirt with Brum in order to learn the location of Yul-Bayur. Brum takes her to the White Island's treasury and shows her Grisha that Fjerda has imprisoned and is experimenting on with jurda parem, then locks her in one of the cells and threatens to use parem on her.
Brum then speaks with Matthias, who is shocked that Brum is happily using parem-drugged Grisha in his war. Matthias realizes that for Brum, the drüskelle cause is not a holy one and he actually enjoys torturing Grisha. After Brum explains his plans for the Grisha and offers to welcome Matthias back into the drüskelle, Matthias chokes Brum into unconsciousness, takes his key to the vault, and returns to free Nina from her cell.
Brum escapes the treasury after Nina, Matthias, and Kuwei Yul-Bo blow up the vault. He, along with a group of drüskelle wearing gray metal masks to protect them from Grisha power, meet the Crows at the Djerholm harbor. Brum shoots Matthias in the chest, but Nina heals him. Nina uses the unconscious bodies of other Fjerdan soldiers to remove the masks from Brum and his drüskelle, leaving them vulnerable to her Heartrender power. Matthias convinces Nina to spare their lives and she acquiesces, though she tears the scalp from his head.
King of Scars
He comes to visit his daughter Hanne when he gets word of her getting in trouble once again. He's in the Wellmother's office, his back to the door, when Hanne and Nina enter the room. Nina recognizes him instantly, even from behind, but with her disguise as Mila Jandersdat, she goes unrecognized by Jarl Brum. Nina reflects on her last meeting of Jarl Brum, and notes that someone took time to sew his scalp back on after her attack and that they had considerable skill. Brum questions Nina, as Mila, pointing out the factory breach and their sudden arrival. He asks questions on her age, her widow status, and her fear. Nina flatters him at one point calling him a "great man" and Nina realizes in that moment that is what Jarl Brum likes, a soft, weak woman who bows to his rule and stature. He demands to question the other two people Nina arrived with, and allows Hanne to continue her lessons.
Rule of Wolves
Personality and traits
Brum had golden hair with gray at the temples, worn long in the style of the drüskelle, until Nina causes him to lose his hair. Nina describes the scar as a "fat pink tail of a rat" that wraps around his skull. He has a lean jaw, a tidy beard, and blue eyes. He is tall and lean. Brum wears the black uniform of the drüskelle, with the silver wolf of the drüskelle emblazoned on his sleeve.
- Rule of Wolves, chapter 2