Here’s where concept sketches really help. By watching your characters in your head and jotting down a few notes or sketches (as in this case) really helps bring them to life once you get around to plopping them into the novel.
Uncle Mordo is one of the main characters even though he vanishes in the first few chapters. But that brief appearance is critical to pulling the reader in emotionally. By spending some time with him before writing he pops to life in the book.