While it seemed like it might be a "mystery box" show, The Leftovers is more of a character-driven story that explores the aftermath of sudden loss and the grieving process. The premise of the Departure--an event where 2 percent of the world's population simultaneously disappeared without a trace--is the catalyst for this exploration.
The Leftovers only works as well as it does because of its complex and nuanced cast of characters. The show's best characters are those who have rich development over the course of the show's 3 seasons and those who best embody the show's themes.
Dean
Both the audience and protagonist Kevin Garvey can't decide if the enigmatic Dean knows more than everyone else and understands the truth of the Departure and the current state of the world, or if he's just an unhinged individual in a world that turned upside down.
A lot of The Leftovers is about the conflict between trying to make sense--often in dangerous and destructive ways-- of the Departure and its aftermath against accepting that the Departure simply happened and that the most important thing is to heal and move forward. Dean represents the former and becomes a significant obstacle in the path toward healing and acceptance.
John Murphy
The Murphy family is introduced as part of The Leftovers season 2 overhaul and quickly become an integral part of the show. In season 2, John Murphy is an angry, bitter, and violent man. His suffering causes him to lash out--often with deadly and devastating consequences--at his town and those around him.
Through the relationship he forms with Laurie, and from some of his life-changing experiences in season 2, John is a changed man by season 3. He has an inner peace, calm, and faith that he never showed before. He and his son Michael also have an improved relationship. With all of the suffering and tragedy that the Murphy family experiences, it is uplifting to see John find peace and become a better man.
Kevin Garvey Sr.
Kevin Garvey Sr. is a bit like Dean in that he leaves the characters and the audience wondering whether he knows more than everyone else or if he is just unhinged. What makes Kevin Sr. a stronger character than Dean is his heart.
His heart is in everything he does and it all comes back to doing what he thinks is best for his son and others. There is something lovable and enthralling about Kevin Sr.'s frenetic energy, his convictions, and the love he has not only for his son, but also for others like Laurie.
Tom Garvey
In the wake of suffering and loss, what people often need most is a renewed sense of purpose and belonging. Tom Garvey seeks this out in the extreme form of cults. In season 1, he works for self-proclaimed prophet "Holy Wayne" and goes to extreme lengths for him. In season 2, Tom tries to give back the purpose and belonging he sought and failed to find as he helps conflicted of the Guilty Remnant escape and later takes on the story of Wayne's magical hugs for himself.
He can only keep this up for so long and eventually follows another cult, this time in the form of Meg Abbott (played by Liv Tyler in one of her best performances) and her Guilty Remnant group to Jarden, Texas. It is only then that Tom finally breaks away from cults and reunites with his family. Like Kevin, he becomes a cop in Jarden, now using his desire to protect others for good.
Jill Garvey
Even though Jill fills the archetypal role of the rebellious teenager in season 1, she is still the most stable member of her dysfunctional family, and the glue that ultimately brings them back together. When her mother leaves her family to the Guilty Remnant and Tom leaves to find meaning and belonging elsewhere, Jill is the one who stays with Kevin, ensuring that at least she and her dad are still family.
Jill becomes the reason why her mother finally speaks again and leaves the Guilty Remnant. Even though Jill is barely in season 3, her father, her mother, her brother, and Nora are able to unite and be a family, largely because of everything Jill did. It is just a shame that Jill's overall presence in the show diminished in each subsequent season.
Patti Levin
As the cult leader of Mapleton's Guilty Remnant chapter, Patti begins as mostly a nuisance to Kevin and the town. Throughout season 1, Patti grows from being a nuisance to being genuinely dangerous and threatening. One of the most chilling examples of this is when Patti has one of the chapter's stoned to death and then goes to Kevin for help in solving a gruesome murder that she orchestrated.
It doesn't stop there as under her leadership, the Guilty Remnant break into people's homes and removes all pictures of the Departed and later on place lifelike dummies of these individuals in the exact locations where they Departed. Even after Patti takes her own life, she rarely leaves Kevin's side and plagues his life in season 2. Kevin goes to extreme lengths to get rid of her, through which he learns the trauma Patti endured, making her a much more tragic and sympathetic individual than Kevin or the audience ever realized.
Kevin Garvey
Justin Theroux's performance is a significant part of what makes Kevin Garvey such a strong character. Kevin is almost constantly dealing with inner turmoil. Even when he seems fine on the outside, a war of emotions and internal conflict is brewing inside of him. Kevin easily could've become an irritating, "woe is me" protagonist if not for Theroux's performance.
Theroux makes Kevin's pain and internal struggles palpable and believable. The raw emotion he brings to Kevin makes him a character who is captivating to watch, even when he makes questionable or disastrous decisions.
Laurie Garvey
In season 1, Laurie Garvey is a member of Mapleton's Guilty Remnant chapter, a woman who left her husband, her children, and career in psychotherapy to a cult where she wears white, stands outside people's homes for hours at a time, and never speaks. What makes Laurie one of the show's best characters is her rich development as she not only leaves the Guilty Remnant, but she becomes the voice of reason and healing in the story.
It is Laurie who helps other characters see that they are making destructive and dangerous choices to search for meaning that is not there. It is Laurie who helps other characters find the acceptance and peace that they have not had since the Departure, and in some cases even before that.
Nora Durst
As someone who lost both her children and her husband during the Departure, Nora is understandably filled with grief and yearns for a lack of closure after suddenly and inexplicably losing those closest to her. Nora is one of the show's strongest characters as she tries to move forward, yet the world tries to constantly pull her back from taking those healing steps.
Whether it's learning that her husband was cheating on her before he Departed, unexpectedly becoming a mother again for a time, or having her life and her homes intruded by scientists trying to understand the Departure, it's as if the world refuses to let her heal. Despite all of these challenges, Nora has the courage and perseverance to do what she needs to get the closure and acceptance that she needs. In many ways, she is the heart of the show, and it only makes sense that one of the best series finales of the past decade is "The Book of Nora."
Matt Jamison
Arguably the best episode in each season is the one that focuses most heavily on Christopher Eccleston's character Matt Jamison. His character always gets in the most absurd situations, yet these situations always end up teaching invaluable and sobering lessons.
Matt's commitment to his faith is irable, but what is most remarkable about him is his character growth. By the end of the series, he understands that he cannot control or find meaning in everything, which enables him to emotionally heal and reevaluate his priorities in life before it is too late.