Sorcery Of Thorns by Barnaby Rogerson

Set in a world where magical libraries house grimoires that can transform into terrifying monsters, the story follows Elisabeth, an apprentice librarian who has grown up among these enchanted books. When an act of sabotage releases a dangerous grimoire, Elisabeth finds herself implicated in the crime. With her life in turmoil, she reluctantly teams up with Nathaniel, a sorcerer with a dark reputation, and his enigmatic demon servant, Silas. As they unravel a sinister conspiracy threatening the magical world, Elisabeth discovers her own hidden powers and the true nature of the libraries she has always revered.