Billy Hargrove is a troubled and aggressive teenager who moves to Hawkins, Indiana, from California with his father Neil Hargrove, stepmother Susan Mayfield, and stepsister Max Mayfield. He is tall and muscular, with bleached-blond hair, blue eyes, and a loud, rebellious style that reflects his confrontational nature. Billy lives in a hostile household dominated by his abusive, controlling father, while his mother’s earlier abandonment leaves him emotionally unstable and deeply insecure. Susan’s passive behavior and failure to intervene reinforce Billy’s belief that power and intimidation are necessary for survival. As Max’s older stepbrother, Billy is possessive, cruel, and controlling, frequently directing his anger and resentment toward her. He is volatile, impulsive, and prone to violence, using aggression to mask vulnerability and fear, though brief moments of hesitation suggest his behavior is shaped by trauma rather than inherent malice.

Max Mayfeild is a tough, street-smart skater girl who hides her grief and loneliness behind sarcasm and independence. She’s fiercely loyal, struggles with her stepbrother Billy’s abuse, and wants freedom and a true friend group, even if she pretends she doesn’t need anyone.

Mike Wheeler is loyal, hopeful, and protective, Mike is desperate to keep El safe while dealing with her secrecy and his own growing feelings. He’s brave but anxious, always trying to do the right thing.

Lucas Sinclair is cautious, practical, and skeptical, often acting as the group’s realist. He’s loyal and brave, but struggles with fear and anger, especially toward threats like Billy. He’s protective of Max, supporting her quietly while trying to keep her safe.

Will Byers is sensitive, anxious, and emotionally vulnerable, still haunted by the Upside Down. He feels isolated and misunderstood, struggling to cope with lingering trauma while trying to stay close to his friends and support them in his quiet, loyal way.

Dustin Henderson is energetic, funny, and endlessly curious, using humor to cope with fear. He’s loyal and brave, quick to defend his friends, and eager to solve mysteries, often acting as the group’s optimistic problem-solver.

Eleven 'Jane' Hopper is quiet, wary, and curious, El is learning normal life while hiding her powers. She’s loyal to Mike and the group, but struggles with fear, confusion, and the trauma of her past.