|“||I'll be there with you, that little fallen angel on your shoulder...||„|
|~ Ruby to Sam Winchester.|
Ruby is the hidden secondary antagonist in seasons 3 (along with Bela Talbot) and 4 of Supernatural. She is a black-eyed demon who acts as an ally towards Sam Winchester, claiming to be there to help him and his brother Dean stop Lilith. However, it was eventually revealed that she was secretly working for Lilith and got Sam addicted to demon blood to further a plan to free Lucifer from Hell.
She was portrayed by Katie Cassidy in Season 3, and by Genevieve Cortese in Season 4.
First appearing in "The Magnificent Seven," Ruby came to Sam and saved him from three of the Seven Deadly Sins (though she was quickly overpowered by the last one, whom Sam himself had to kill) wielding a strange knife that could kill demons.
Ruby returned in "Kids Are Alright," first pretending to be another hunter and offering advice to Sam, letting him in on the fact that Azazel had wiped out almost all of Sam's late mother Mary's family. She then revealed what she really was to Sam, but claimed she was different, saying she cared and could still remember being human.
In "Sin City," Ruby came to Bobby Singer to help him work on the Colt. With her help, Bobby managed to make some new bullets for the Colt, ones that could kill near anything.
Later, when Sam and Dean faced witches in "Malleus Malficarum," Ruby returned to help the two brothers. However, Astaroth, the demon who had granted the witches all of their powers, knew Ruby and revealed that she was once a witch "back when the plague was big" and it was Astaroth who corrupted her. Astaroth also warned the brothers that Ruby was a "lying whore"; however, in the conflict and with the help of another witch who came to her senses, Dean managed to kill Astaroth.
Ruby again returned in "Jus in Bello" when the brothers were trapped in a police station by Lilith's forces. She tried to convince them to sacrifice one of the people trapped along with the Winchesters as part of a spell to kill all the demons and save them all. However, Dean refused, and as such, Ruby decided to leave. Dean managed to formulate his own plan which stopped all the demons, but one escaped and Lilith herself went to the station after the Winchesters left, and killed everyone there. Ruby came to the Winchesters' hotel room to inform them of what happened and to criticize them for not going with her plan.
In "No Rest For the Wicked," Sam summoned Ruby, as time was running out until Dean's deal came due; he wanted her knife to kill Lilith. However, Ruby was unwilling and she was more interested in encouraging Sam to use his own powers. Dean managed to manipulate her disdain of him into attacking him and getting herself trapped in a devil's trap; he then took the knife and left her. However, during the assault against Lilith, Ruby returned. Dean's time ran out and Lilith's hellhound came. Ruby demanded her knife, claiming she could fight them off. However, Dean realized (thanks to his last hours actually letting him see demons for what they really were) that she was in fact in Lilith. Lilith then admitted to having banished Ruby and then had the hellhound kill Dean.
While Dean was in Hell, Ruby managed to return. To appease Sam, she took the body of a comatose woman who had just been taken off life support. She then began trying to teach him that he had the power to stop demons, powers originally given by Azazel giving him demon blood as a baby, and could be enhanced by drinking more demon blood, her own blood. Sam was unwilling and instead went off to try and kill Lilith, only to walk into a trap. Ruby arrived and tried to save Sam, but she was quickly overpowered by the other demons. To save her, Sam actually did access his powers and managed to exorcise the demon. Afterwards, he began to go with Ruby's methods, thus beginning his demon blood addiction.
Upon Dean's return in "Lazurus Rising," Sam went to Ruby to ask about why the demons were so scared, and Ruby revealed that no demon freed Dean from Hell, saying it was something much more powerful. It was revealed to be the angel Castiel.
In "Are You There, God? It's Me, Dean Winchester," upon Sam telling her about the angels, Ruby went into hiding, afraid they would kill her.
In "In the Beginning," when Sam once again slipped away from Dean to meet Ruby to exorcise another demon, Castiel took Dean to watch this near the climax, to warn him that his brother was now walking down a slippery slope.
Immediately afterwards, in "Metamorphasis," Dean burst into the place furiously and a small fight broke out between him and Ruby. Ruby managed to knock Dean down, but Sam broke up the fight, and Ruby left the two brothers to settle the matter.
Returning in "I Know What You Did Last Summer," Ruby arrived at the church where Anna Milton was hiding, to warn the brothers that Alastair was coming for her. She tried to encourage Sam to use his powers on him, but Alastair proved too powerful and she was forced to flee, taking Anna to safety. She later possessed a maid to inform the brothers where she was keeping Anna. Back in her regular body, they met up, when Uriel and Castiel arrived. Terrified of the angels, Ruby backed away.
In "Heaven and Hell," with Castiel and Uriel revealing that they had orders to kill Anna, Ruby agreed to help the Winchesters to try and restore Anna's grace. In the process, she was kidnapped by Alastair and tortured by the brutal demon for information, finally breaking so he would arrive the exact same time the angels did for Anna. Ruby managed to recover from the torture, but didn't find the process pleasant.
In "Criss Angel Is a Douchebag," Sam finally contacted Ruby, deciding to completely go along with her plans because he doesn't want to keep doing this for the rest of his life. This caused his addiction to only get worse, however. By now, the demon blood was seriously changing Sam, causing him to become arrogant and cold in personality.
In "On the Head of a Pin," Ruby once again appeared to Sam to help him find where the angels had taken Dean and make certain he was near full power. In this state, Sam was able to kill Alastair, but by now, his addiction had gotten to the point where, in "The Rapture," he actually killed a demon's vessel so he could drink the demon's blood after he began experiencing withdrawal symptoms. As such, Dean and Bobby locked him in Bobby's panic room to detox.
In "When the Levee Breaks," Sam managed to escape and again went to Ruby, now well over the limit and actually only borderline human. Dean tracked him down and tried to talk him out of it, but Sam couldn't be shifted. Furious at what Ruby had done to his brother, Dean attacked her, but Sam attacked Dean. Empowered by the blood, he beat his brother and almost choked him to death before leaving with Ruby.
During "Lucifer Rising," Ruby convinced Sam to outright murder a innocent woman possessed by a demon so that he could drink all the blood in order to be ready to kill Lilith and thus prevent the Apocalypse. However, Dean learned from Castiel that it was all a trick and that killing Lilith wouldn't stop the apocalypse, but actually start it. When Dean arrived to stop Sam, Ruby telekinetically closed the doors to stop Dean. Sam killed Lilith, but in doing so, freed Lucifer from Hell. Overjoyed, Ruby revealed the truth and assured Sam not to worry, as Lucifer would greatly reward him for what he had done. When Dean burst into the room, Ruby smugly told Dean he was too late, but Dean doesn't care that he is. Sam grabbed her from behind as Dean stabbed her to death with her own knife.