Lord Carlo Boreal (taking an alias of Sir Charles Latrom in Will's world) is a powerful and influential man in both Lyra's world and Will's. He is a lover of Mrs. Coulter - although she uses him more than he does her, and she ultimately murders him.
Lord Boreal is introduced at Mrs. Coulter's cocktail party in The Golden Compass and we learn that he is involved in the General Oblation Board among other organisations. His dæmon is a serpent with an emerald head and gold-rimmed black eyes.
Lord Boreal is evidently similarly powerful in Will's world, knighted and rich under his alias Charles Latrom (note that Latrom is mortal spelled backwards). He hides his serpent dæmon in his sleeve. In The Subtle Knife he steals Lyra's alethiometer in order to blackmail she and Will into procuring him the knife.
|"A powerful man in his sixties, wearing a beautifully tailored linen suit and holding a Panama hat [...] his gray hair was brushed neatly back from his smooth, tanned, barely wrinkled forehead. His eyes were large, dark and long-lashed and intense, and every minute or so his sharp, dark-pointed tongue peeped out at the corner of his lips and flicked across them moistly."|
|The Subtle Knife, Chapter ??|