The best character, all other arguments are null and void.
  1. Harry Potter and the Sorceror's Stone
    No Lupin
  2. Harry Potter and the Chamber of Secrets
    No Lupin but they make a lot of derogatory comments about werewolves, which is important Lupin world building.
  3. Harry Potter and the Goblet of Fire
    No Lupin but we know he exists at least.
  4. Harry Potter and the Order of the Phoenix
    Small amounts of Lupin, but some golden moments, like when he shows up at the Dursley's, surprising Harry, and when he and Sirius try to explain James to Harry.
  5. Harry Potter and the Deathly Hallows
    Technically quite a lot of Lupin but the one chapter where he tries to leave Tonks makes me so sad so it can go here.
  6. Harry Potter and the Prisoner of Azkaban
    There's an alternate universe where Lupin is just a really nice, really good teacher. I like that universe.
  7. Harry Potter and the Half Blood Prince
    I know, you're thinking "actually this doesn't have that much Lupin" BUT once you know about Lupin and Tonks (number one OTP forever) and you reread this book it's really a basket of gifts for your imagination.