The latest addition to the Hawkins crew, Eddie is the leader of the high school Hellfire Club. He's an outcast and burnout with a weird reputation, especially after he's suspected of killing popular cheerleader Chrissy (who was actually killed by Vecna).
In the end, Eddie becomes a huge asset to the Hawkins crew, helping them unearth the truth about Vecna, bonding with the others (especially Dustin), and battling right alongside them. In the end, he dies a hero's death, distracting the monsters in the Upside Down long enough for his friends to knock Vecna out, then dying in Dustin's arms.