A movie's success depends on many factors. Namely, the quality of the writing, the talent of the cast, the director's experience, the cinematographer's keen eye, the storytelling aptitude of the editor, and the composer's creativity (to name a few). But the one that stands out above all is an excellent protagonist.

RELATED: The 10 Toughest Horror Movie Protagonists

A worthy protagonist must have many qualities and ranking high should be the character's relatability. A strong main character with a good story is almost always a recipe for success. But sometimes, a supporting character emerges whose story is more intriguing; a character who is so well-written that sometimes they outshine the protagonist.

Alfred Pennyworth in 'The Dark Knight' Trilogy

Michael Caine as Alfred Pennyworth in The Dark Knight

Better known as Batman's butler, Alfred (Michael Caine) became Bruce Wayne's (Christian Bale) legal guardian after the death of his parents. Later, he was his partner in crime, helping Bruce become Batman.

Relegated as just a butler in previous films, true fans of the character knew that there was more to Alfred than just being a simple servant. An ex-member of the British Special Air Service, many of Alfred's skills were put to good use in helping Bruce keep Gotham City safe. And the bottom line is that without Alfred's help, there would be no Batman. But mostly, Alfred was a paternal figure for Bruce and the only real family he had left. And he never wanted this life for the person who was basically his son.

Ramona Vega in 'Hustlers'

Ramona and Destiny in Hustlers

A young stripper, Destiny (Constance Wu), strikes a friendship with an experienced stripper, Ramona, who agrees to take her under her wing. However, the financial crisis of 2007-2008 makes it harder for them to earn money stripping. Ramona then proposes a scheme to drug and rob Wall Street men.

Although it's easy to empathize with Destiny's personal situation, Ramona's imposing presence throughout the film (based on a true story) stirs the audience's attention towards her. She's the ringleader, the maternal figure, the protector of all the young protégées she enlists in her elaborate plan. Played by Jennifer Lopez, who steals every scene she's in with this juicy role, it isn't hard to root for Ramona and her hustlers despite the illegality of their actions.

Captain Edward John Smith in 'Titanic'

Bernard Hill as Captain Smith in Titanic
Image via 20th Century Fox

On her maiden voyage, the Titanic hit a massive iceberg and sank to her doom, killing over a thousand passengers. Her Captain, Edward John Smith (Bernard Hill), went down with her, realizing he was to blame for her demise. This was the backdrop to the story of two star-crossed lovers who met onboard the ship.

The story of Rose and Jack was enthralling. But the real drama was unfolding in the ship's control room. Led by his ego, Captain Smith ignored warnings of icebergs and pushed the engines forward to arrive before the estimated time. These decisions would prove catastrophic, as the Titanic foundered in the icy waters. Yes, Jack died, but nothing can be more tragic than being responsible for the deaths of more than 1500 innocent souls.

RELATED: 7 Strange Titanic Films That Aren't James Cameron's 'Titanic'

Miss Minchin in 'A Little Princess' (1995)

Eleanor Bron as Miss Minchin in A Little Princess

Miss Maria Minchin (Eleanor Bron) is the headmistress of a boarding school. Her severe rules are law until the day a pleasant little girl named Sara (Liesel Matthews), with a particularly vivid imagination, arrives at the school.

Based on the classic book by Frances Hodgson Burnett, the movie hints that Miss Minchin had a harsh childhood that made her heartless. But unspoken pain and anger were hidden underneath her cold exterior. Perhaps the most perplexing and intriguing aspect of Miss Minchin's story is that her sister Amelia was her complete opposite. In the end, her character is somewhat redeemed. Dressed in rags and covered in soot, Miss Minchin was now a chimney sweeper working with a young boy she once mistreated.

Burnham in 'Panic Room'

Forest Whitaker as Burnham in Panic Room

Burnham (Forest Whitaker) and two accomplices enter a townhouse, looking for some hidden money. Surprised by the occupants, complications ensue when the mother and daughter run and hide in the panic room. The same room where the money is hidden.

Burnham is not above breaking the law but draws the line at hurting people. Convinced to stay and to carry on with the plan once reminded why he's there, Burnham's story is one of despair. He is in a custody battle for his children and needs the money to pay the lawyers. That bit of information, combined with his refusal to hurt anyone, makes it easy to be invested in this character.

Norman Nordstrom in 'Don't Breathe'

A blind man holding a gun

Rocky (Jane Levy) and her friends rob houses for a living. Finding out that a war veteran is hiding a significant amount of money in his home, the group decides to rob him, thinking it will be easy because the man is blind.

Sympathy for Norman (Stephen Lang) turns to shock when Rocky and Alex find a young girl held captive in the basement. Norman goes from being the victim to the evil antagonist. The girl is responsible for the car accident that killed Norman's daughter and is pregnant with Norman's baby to replace his dead daughter. In the end, Rocky outwits Norman and escapes with the stolen money. The complexity of Norman's character is renewed as he doesn't tell the police that anything was stolen from his home.

Inigo Montoya in 'The Princess Bride'

Mandy Pantinkin as Inigo Montoya in The Princess Bride

As a child, Inigo Montoya (Mandy Patinkin) saw his father die at the hands of a six-fingered man. He made it his life's purpose to find the man responsible for his father's death and knows precisely what he will tell him when he does.

Introduced as one of the villains who kidnapped Buttercup, Inigo becomes Westley's skilled ally, helping him storm the castle to save Buttercup. Inside, Inigo finds his father's murderer and challenges him to a swordfight. Defeated, the man pleads for his life by offering Inigo whatever he wants. Inigo then proceeds to kill him, knowing the man cannot give him his father back. It's a satisfactory conclusion and the kind you find in storybooks.

RELATED: 10 Best Movie Princesses Who Are Not from Disney

Oda Mae Brown in 'Ghost'

Whoopi Goldberg as Oda Mae Brown in Ghost

She made a living scamming people wanting to communicate with their dead loved ones. But the day the ghost of Sam Wheat (Patrick Swayze) finds her, Oda Mae (Whoopi Goldberg) realizes she is a psychic. Unwillingly, she helps Sam find his murderer and protect his girlfriend, Molly (Demi Moore).

There is a reason Whoopi Goldberg won an Oscar for this role. She practically stole every scene she was in. Although the story is tragic, it's hard not to laugh at Oda Mae's odd predicament. She's the only one who can hear Sam, and it's hard to believe her because of her shameful criminal history of swindling people. Still, she begrudgingly helps Sam even if it means having her two sisters think she lost her mind.

Hit-Girl in 'Kick-Ass'

Chloë Grace Moretz as Hit-Girl in Kick-Ass

An ex-cop, framed and sent to jail, loses his wife by suicide while he is gone. He decides to become a vigilante and raise his daughter to be one too. Going as Big Daddy (Nicolas Cage) and Hit-Girl (Chloë Grace Moretz), the duo team up with the newbie Kick-Ass (Aaron Taylor-Johnson).

Raised in a world of guns, knives, and combat, Hit-Girl is not an ordinary girl, and she longs not for puppies or dolls but a balisong knife. With a purple wig, a superhero costume with a plaided skirt, and a foul mouth, Hit-Girl gets a kick out of killing bad guys. But what once was a game becomes a mission when her father is tragically killed.

Luna Lovegood in 'Harry Potter And The Order of The Phoenix'

Evanna-Lynch-as-Luna-Lovegood-in-Harry-Potter-And-The-Order-of-The-Phoenix-1

This Harry Potter (Daniel Radcliffe) movie installment introduces Luna Lovegood (Evanna Lynch), a peculiar yet charming girl who will share an unexpected friendship with Harry.

Unperturbed about what people think of her, Luna is isolated by her schoolmates for being weird. When Harry himself is isolated for claiming, against everyone's belief, that Voldemort is back, the two befriend one another. He realizes that Luna is far from the loony girl she's perceived to be. Quite insightful, Luna impresses Harry with her views on Voldemort's strategy in trying to keep Harry alone, so he's much less of a threat. She and Harry can both see thestrals, horse-like winged creatures that can only be seen by people who have seen death. Luna is a skilled witch with fascinating knowledge about the magical world. To borrow Harry's words, she is simply cool.

NEXT: 10 Supporting Movie Characters Who Deserved Their Own Spin-Offs