Here is a list of the main cast and characters on the CW series
Supernatural.
Jensen Ackles as Dean Winchester (Seasons 1-10)
The older of the Winchester boys, Dean has felt a responsibility to protect his brother since a demon tried to take Sam as a baby, killing their mother in its effort. He values family above all else and is deathly afraid of losing them. He was close to his father throughout his childhood and adheres to his dad's teachings about becoming a "hunter" of evil supernatural beings. However, he's insecure that Sam might actually be his dad's favorite child. A lifelong hunter, Dean is street smart and has little time for lasting relationships, as witnessed by his long line of romantic flings. He has a bad boy reputation, enhanced by his sarcasm, leather jacket and 1967 Chevy Impala, in which he constantly blares "classic rock" music.
Jared Padalecki as Sam Winchester (Seasons 1-10)
Sam is the "book smart" of the Winchester brothers, boasting a vast knowledge of supernatural beings and spells. He reluctantly left college to pursue a life as a hunter when his father went missing and his girlfriend was killed by the demon that murdered his mother. Unlike Dean, he rebelled against his father's strict demon-hunting ways and tried to escape by going to college. However, he's drawn back in by the death of his girlfriend, which reignites his thirst for revenge. His single-mindedness makes his demeanor more businesslike and less jovial than Dean. He's recently developed psychic abilities -- mostly premonitions, but also the ability to move objects with his mind -- a gift that is tied to the deaths of his mother and girlfriend.
Jeffrey Dean Morgan as John Winchester (Seasons 1-2)
John raised his boys with no-nonsense, militaristic discipline, training them to become "hunters" in order to get revenge on the demon that killed his wife. Dean follows his orders faithfully, but John has a contentious relationship with Sam, who rebels against the hunter lifestyle. John worries about the safety of his kids, but the death of the demon he seeks is the ultimate goal. He belongs to a loose alliance of hunters around the US who've dedicated themselves to exterminating malevolent supernatural beings, and John disappears for stretches as he investigates unexplained phenomena. One of his extended disappearances leads Dean to reconnect with Sam at college and draw him back into the hunter life.
Jim Beaver as Bobby Singer (Seasons 1-8)
Bobby is an old hunter friend of John's who provides the Winchesters with both physical support and first-hand knowledge from his years of experience battling demons and other creatures of the night. Unlike John's nomadic lifestyle, Bobby remains stationary, running an auto salvage yard. He became a hunter after he was forced to kill his wife when she became possessed by a demon.
Katie Cassidy as Ruby (Season 3)
Ruby is a demon with a heart of gold. She was a witch during the Middle Ages who sold her soul to a demon, but despite the passage of hundreds of years, she has retained some level of humanity. She has a special interest in Sam and his destiny and uses a magical dagger with the power to kill demons to help him live to fulfill it. Dean doesn't trust any demon and urges Sam to kill Ruby, but Sam hopes that she can help him save Dean's soul.
Lauren Cohan as Bela Talbot (Season 3)
Bela is a con-woman and thief who operates within the hunter realm in order to acquire supernatural relics and sell them to wealthy collectors. She's manipulative and distrustful, playing both sides of any equation and always looking to make a deal. Her contacts can be helpful to the Winchesters -- but always at a price.
Nicki Aycox as Meg Masters (Season 1)
Meg is a young woman possessed by a demon -- the child of the demon who killed the Winchester boys' mother -- that uses her to try to kill John and steal "the Colt," a mystical revolver that can kill anything. When possessed, she is a ruthless, cold-blooded killer, but in reality she is just a normal human whose body is used as a vessel for evil.
Alona Tal as Jo Harvelle (Season 2)
Like Sam and Dean, Jo is a second-generation hunter. Her father was a friend of John's who died while they were fighting a demon together. She holds a bit of a grudge against the Winchesters for her dad's death but is nonetheless secretly attracted to Dean and helps him in times of need. Jo is headstrong and wishes to break away from her mother so that she can become a solo hunter.
Samantha Ferris as Ellen Harvelle (Season 2)
Ellen is Jo's mother. She's tough but protective of her daughter, forbidding her to go hunting on her own -- a fear stemming from the death of her husband when Jo was a child. Ellen runs a bar called Harvelle's Roadhouse that serves as a hunter hangout. She doesn't blame John for her husband's death and helps the Winchesters when needed.
Sterling K. Brown as Gordon Walker (Seasons 2-3)
Gordon is a hunter who developed a grudge against vampires as a teen when his sister was turned into one. His extreme hatred has turned him into a killing machine, and he's willing to sacrifice anyone -- including the Winchesters -- to get revenge. His distrust for all things supernatural leads him to believe that Sam's psychic ability means that he's the Antichrist and thus deserves to be killed.