Following Dean's incarceration in Hell, their relationship took a big leap forward as they began to get physically intimate. Ruby was also entirely responsible for his demon blood addiction. She was ultimately killed at the hands of both brothers.
Ruby knew about Sam before they met. She knew he was the last surviving special child that Azazel had plans for. Before they meet face to face, Ruby watched Sam from afar. Sam did notice Ruby following him; however, when he turned around, she would vanish. They finally meet when Sam is overwhelmed by three demons at once, and she conveniently steps in.
|“|| Who the hell are you?"|
"I'm the girl that saved your ass.
— Sam and Ruby
in The Magnificent Seven
Sam and Ruby meet when Sam is about to be killed by a demon. She comes up and kills them all using her special knife. Sam had recognized her as the girl following him earlier, and wondered who the hell she was.
After that, she pops in on Sam in a diner and starts eating some of his french fries. Sam asks about her knife, but Ruby doesn't tell him much other than it comes in handy when tracking down demons. Sam follows up by asking why she is following him. She remarks she likes a tall man and that she's interested in him. The sole survivor of Yellow Eye's special children. She continues on by telling Sam there still are plans out there for Sam, especially after what the yellow-eyed demon did to Mary and her friends. Sam looks confused, so Ruby grabs his hand and tells Sam that he has some work to do and to call her when he is done.
Sam calls Ruby later and tells her his discoveries. Ruby tells Sam that Yellow Eyes was covering his tracks. Sam demands her to tell him who she really and Ruby reveals she's a demon. She also tells Sam she can help with getting Dean out of his deal. In Sin City, Sam threatens Ruby with The Colt (which she fixed) when Ruby threatens to take it away. Ruby tells Sam if he kills her, she can't help Dean. She tells Sam to think of her as the little fallen angel on Sam's shoulder when she tells Sam hes going to have to do things that go against his nature. Before that she and Sam got into an argument about killing two demons (Sam argues it was also two humans as well).
Later, Sam begins to start trusting Ruby. She and Sam are even talking about things without Dean knowing. We see this in Jus In Bello when she offers a plan that will kill all demons in a 30 miles radius. All they have to do is kill a virgin, which Dean hastily protests against. Ruby asks Sam, and he is a bit more hesitant to answer. Sam also knows about Lilith thanks to Ruby's intel, but he doesn't tell Dean. When her plan is denied, she leaves saying she doesn't want to watch them lose.
As Dean's time is almost up and they figure out Lilith has Dean's contract, Sam wants to call Ruby for help. Which he does despite Dean's wishes. Sam asks Ruby if she knew Lilith had Dean's contract, and she answers yes. Sam asks why she didn't tell him, and she responds that Sam wasn't ready. Ruby continues on by saying, "If I told you, you two yahoos would’ve just charged after her half-cocked. And Lilith would’ve peeled the meat from your pretty, pretty faces." Sam retorts that they're ready now. Ruby tells Sam she knows how to save Dean, but it's not her who will save him, it's Sam. Sam is confused, Ruby tells Sam it's the powers Azazel gave him and Sam can use them to wipe Lilith off the map. Sam doesn't believe her.
Ruby talks about how Sam doesn't like the idea of being different. She tells Sam to suck it up and learn. Ruby finishes by saying that Sam can save his brother and she can show him how. Then Dean comes and traps her in a devil's trap (and grabs her knife). In the end, Sam chooses Dean over Ruby. But he does show concern for Ruby as they're getting ready. Ruby does manage to escape and attacks Dean, but Sam stops her by putting the knife to her neck. When it hits midnight, Sam desperately asks Ruby to teach him how to save Dean. But it's too late. This all happens in episode 16, of season 3, No Rest For The Wicked.
|“||You didn't need the feather to fly. You had it in you the whole time, Dumbo!||”|
— Ruby to Sam
in Lucifer Rising
Ruby saves Sam's life when Sam no longer has the will to live. When Sam questions where Ruby grabbed the body, and then tells her to get out, he has no use for her. So Ruby goes and grabs a brain dead patient (there isn't a soul in the body) as her new body for Sam. When she brings up psychic matters again, Sam agrees. Thus, Ruby begins to teach Sam how to use his powers, but Sam can't get it right and Ruby kills the demon for taunting Sam.
After burying the body, Ruby confronts Sam and kisses him. Sam draws back quickly and asks Ruby what she's doing. Sam is resisting the temptation because he doesn't want to sink so low as to sleep with a demon. Ruby assures Sam it's okay as it's just her in the body and seduces him. Sam succumbs, and they have sex.
Then Sam hears Lilith is in town and goes after her. Ruby tries to stop Sam, but Sam pulls the knife on her and leaves. When Sam gets overwhelmed, Ruby comes and saves Sam. Sam returns the favor and is able to exorcise his first demon with his mind. It's believed around this time Sam started to drink demon blood.
When a resurrected Dean shows up at Sam's door, Ruby pretends not to know Dean. Sam plays along, and pretends not to know Ruby, implying that part of him knows that what he's doing is wrong. Instead, he treats it like a random hook up.
When Sam goes to investigate the diner, Ruby meets up with him, commenting on his progress. Sam asks Ruby what the hell is going on, and Ruby answers that she doesn't know. Sam tells Ruby they think a high level demon pulled Dean out, but Ruby shoots this theory down. Ruby asks Sam if hes gonna tell Dean about what they're doing and if they don't tell Dean, he's gonna be pissed. Sam responds that Dean doesn't like this psychic stuff and will try and stop him. Ruby tells Sam that she is not on Dean's good side, and is not going to come between them. Sam says that he doesn't even know if what he's doing is right or if he trusts Ruby or not. But he wants to continue.
Later on, Ruby approaches Sam about Dean being rescued by angels. When Sam confirms it, she attempts to leave. Sam asks her what's wrong and Ruby replies that angels won't care that she's helping, they will still kill her. She continues by saying that the angels scare her and tells Sam to be careful. Sam responds by saying he is not scared of angels. Then Dean finds out what Sam's doing (Metamorphosis) and Sam stops Dean from attacking Ruby.
In I Know What You Did Last Summer, Sam drops everything when he sees Ruby. She gives Sam a tip about a girl the demons want. When they locate the girl, Ruby comes in telling them demons followed them, and then the demons attack. Ruby takes Anna for her own safety. Sam tells Dean why he trusts Ruby (story is above) and then Ruby comes in to tell Sam where she is. In Heaven and Hell, Ruby helps Sam in his plan to bring the angels and demons together.In Criss Angel Is A Douchebag, Ruby comes to Sam's room, not too happy. She accuses Sam of wasting time because now, thirty-four of the seals have been broken. Sam counters that he doesn't know what the seals are or how many are there. Ruby suggests that Sam go after the source of all their problems: Lilith. Sam mentions to Ruby that it's not the psychic thing, he has a legitimate problem. Ruby admits she knows what he has a problem with, but tough. She continues on by saying that Sam should just admit he likes it. Sam plays dumb and Ruby gets angry and leaves. Though Sam calls Ruby and starts up again.
It is revealed in On The Head Of A Pin what Sam didn't like to do, but did it anyways. After locating his brother, Sam tells Ruby he needs more, and she tells Sam he can have it. Demon blood is the reason why Sam's abilities were growing. Ruby is slowly making Sam a demon blood addict, Sam just doesn't know yet.
Then Sam gets locked in the panic room by Dean, but eventually escapes. When he sees Ruby again, he yells at her for not answering his calls. Ruby responds by saying that she can't answer when she on the hunt for Lilith. Then Ruby lets Sam feed while she silently smiles. Ruby tells Sam his appetite has gotten bigger and she can't supply him with any more blood. She follows up by saying she has a lead on demon who's close to Lilith. Then Dean shows up and tries to kill Ruby, but Sam stops him. In this moment, Sam chooses Ruby over Dean.
So in Lucifer Rising, they kidnap and torture the demon for information on Lilith's location. Then Ruby tells Sam that they are going to need to bleed the demon dry so Sam can have enough power. Sam is not so sure about it and is even more unsure when the demon lets the human out. Ruby isn't too happy the demon did this (she knows Sam is still soft-hearted and dislikes hurting innocent people). After a fake message from Dean, Sam agrees to do it Ruby's way. Then she and Sam head into the church where Lilith is. Once Sam kills Lilith, Ruby is ecstatic that Lucifer has finally been released and reveals that she was working for Lilith all along, manipulating and tricking Sam every step of the way to ensure that he broke the final seal.
Now knowing her betrayal, Sam curses her and attempts to use his power on her but is drained. Ruby tells a horrified Sam that he never really needed demon blood to do the job - all his powers were the result of the various decisions he made over the past year (i.e. choosing her over Dean, drinking her blood, believing that he knew what he was doing and not listening to others). She also promises him that Lucifer will reward him in ways he never imagined. When Sam demands to know why he had to be the one to do this, Ruby starts to explain that it had to be him when Dean bursts into the chamber. Sam grabs Ruby's arms while Dean stabs her with her own knife, killing her.
Alternate RealityEditIn "The French Mistake" when Sam and Dean are thrown into the lives of Jared and Jensen, Sam discovers to his shock he's married to "Ruby" - actually Genevieve Cortese, the actress who plays Ruby. Seeing her, Sam recalls the terrible experience he had with Ruby and is put off by her as Genevieve is confused by this behavior.
After she returns from a charity event, Sam asks her about any supernatural events that has happened. She answers, "Yeah, on your TV show." Genevieve comes to the conclusion that Jared (Sam) has been "Sam" for too long. She kisses him and grabs his hand as she takes him upstairs, presumably to have sex, while Sam goes along a bit reluctantly.
- Jared Padalecki said in a convention that Sam believes he was in love with Ruby.
- Genevieve Cortese, who played Ruby in Season 4, is married to Jared Padalecki (Sam) in real life and they have three children together; Thomas (born on March 19, 2012), Shepherd "Shep" (December 22, 2013) and Odette (born on March 17, 2017). Genevieve later appears in The French Mistake as herself.
- Ruby is the only demon so far with whom Sam has had a romantic relationship with.