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Writer: Bob Berens
Director: Phil Sgriccia
Air Date: February 17, 2015


If you murder a murderer who wants to be murdered are you a murderer?
If you don't mind crawling like a cockroach, you might consider a re-watch of this
much anticipated showdown between Dean, Cain and the Mark.
Time for Wednesday's RearView Review. "Let's do it!" scuttle, scuttle....


Tommy's crying in his cell. A Corrections Officer (Simon Chin) bangs his night stick, "Lights out in five."
Tommy (Roman Blomme) peers out, "Hey, any mail?" Apparently, the usual "postcards from anti-penalty
folk, proposals from your lady admirers. You said you were done with those."
Tommy calls to the retreating guard, "Hey, how's your wife, by the way? Amanda? ...
You know I killed an Amanda once? My fourth. I'd do your wife the same, buddy, only slower."
The Officer returns to Tommy's cell, "Two weeks from Tuesday, Tommy."
Tommy eggs him on, "Let's do it! Let's do it now, tonight!"
The Officer signals to the Central Control Officer (Martin Budny) and leaves for coffee.


Tommy sits on his bunk. A man's legs appear before the gate. Lights flicker. He's in the hallway.
Feet walk the yellow line proceeding to Tommy's cell. The Officers discuss Tommy Tolliver's verbally assaulting "usual grief."
For a moment, the Officers see a man's shadow. The surveillance monitor goes black.
When light returns, no one's there. The Officers pass it off.


Tommy wheels around. Cain's in his cell. "Who the hell are you? How'd you get in here?"
Cain (Timothy Omundson) has many names. "The father of murder is one of them. And by the state's count,
you've taken six lives yourself, Tommy. Although by my count, it's nine. Oh, come on.
You aren't one of those 'it wasn't me' type fellas, are you? Because I know you're a killer, just like me."
Clenching his fists, Tommy admits, "Yeah, I did it," and throws a punch, quickly caught by Cain.
With a wave of his fingers, Cain immobilizes Tommy's arm.


"Honesty. That's good. That's the spirit! Now, I bet you're wondering what I'm doing here.
Did I come to punish you, or save you?" Cain embraces him, "Well, the truth is, Tommy, I'm here to do both."
He stabs a knife through Tommy's stomach. The knife sticks out his back.
They vanish. A blood drop falls.
(Less is more.)



Polunsky Unit. West Livingston. TX.

On the road to the prison, Dean tests Sam's knowledge of Serial killers.

Dean considers it a whole new freaky side of Sam. Sam maintains it's a hobby.
Dean disagrees, "Bass fishing, needlepoint, that's a hobby, okay?
Collecting serial-killer stats, that's an illness."

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(P.O.V. Riding in the back seat! O.M.G. Perfect shot. See Dean in the rear-view mirror?
Oops, Dean didn't use the signal lights. We're riding in BABY!)

They pull up to an intercom/camera and flash badges, claiming to be from the Office of the Inspector General
with an appointment with the Warden. Investigating Tommy Tolliver's "Houdini-esque escape," Sam relates the stats,
"convicted of 6 murders back in '09, but those are just the ones that stuck... he escaped from a locked cell on death row."
Dean figures this might be in Sam's "Wheel house" or "hobby."


We get a cockroach view of Warden Skeiff's butt, as he squats looking at the blood splotch.
The Warden (Keith Martin Gordey) welcomes "Inspectors Moore and Ranaldo" to Death Row.
Dean pulls out the EMF. Sam blocks the Warden's view.
The Warden recalls, "The night Tolliver disappeared,  our little ship was running as tight as ever... "
(Scuttling out of Dean's way, we watch crouched beside the cot.)


The tabloids claim the escape was "some dark miracle."
The Warden escorts them to Central Control. Footage shows dimmed lights and a shadow.
Dean asks for a zoom. "Do it. Freeze it. Blow it up."


Dean stares at the silhouette. His heart pounds. He rubs his forearm.



Castiel ignores the ringing phone on a desk in an abandoned classroom.
He's torturing a Demon (Andrew McKenzie) bound in a devil's trap. He refuses to answer until Castiel slices him.
Cain kills demons so they keep their distance but, "He's been seen, the past few months,
making passes through Boggs's Marsh, one county over."
Castiel points the blade at the demon's eye, "And, that's all you know?" The Demon swears it.
Castiel drops his arm. The Demon sags in relief.
Lit like an angel, unexpectedly, Castiel lunges, driving his blade in the Demon's guts.



A Crossroads Demon (John Mackie) pleads before Hell's Court (topside).
It's only fair that Albon shares the credit for 86 souls captured.
Crowley, playing a hand held game, tells him to get to the point.
The Demon wants "Equal credit for equal work." Crowley says "Fine."
Rowena, hidden behind a pillar, doing her needlework "hobby", mumbles, "The wee man! Agh!"
(Never give a witch thread, or string. Knot smart.)


Crowley asks if she'd like to share. At first she says, "Oh, No. It's just not what I would do."
Crowley requests she "enlighten" them. What Would Rowena Do?
She alludes to the Biblical 'splitting the baby in half', but she's not talking about splitting the reward;
she's referring to the whining Demon. She wants him split in half. "I'd cut this puling,
pathetic, greed-grubbing git in two, literally. Then, I'd nail his bloody halves to the doors of the court;
a reminder to all, not to waste the King's time. Whiners beget whiners. You can't reward behavior like that.
It's why I never gave in when you asked for sweeties as a child, no matter how much you cried.
You were a very chunky child, darling. Bit of a bloater."
Crowley says, "That's enough."
Crowley instructs his Right Hand Demon to do... "What she said."
Demon guards drag the protesting Demon away.
Rowena smirks, "That's my boy."



Dean carries a tray with pupusas from the Guanaco Truck back to Baby. No luck reaching Cas.
Sam fills him in on his research. Tommy's father, also a convicted felon, is missing. Dean's phone rings.
It's Cas. Dean asks Caper style, "Where you at?" Cas is in Illinois.
Dean updates him on Tommy's disappearance.
Cas, in a barren clear cut filled with burial mounds, holds Tommy's sneaker. "He's dead."
Dean says they'll come to him; but, Cas senses someone watching, "I'll call you back."




"Hello, Castiel." Cain's cleaning up his mess.
He resisted the Mark's blood lust, but killing Abaddon's demons reawakened it.
Castiel points out those were "demons not humans." Cain picks up a soiled teddy bear,
"Humans. The Mark thirsts for all kinds." Castiel calls it a "massacre" and Cain announces it will soon be a "genocide."
He killing all of his bloodline, his "poison issue." He will feed the Mark with his own "blood."
At most, he cull 1 in 10.
Cain asks how Dean's doing. Castiel reveals they're losing Dean to the Mark. They need a cure.
Cain scoffs, "there is no cure." He's "living proof of that."
He'll get to Dean, claiming Dean as one of his blood and destined to die. 
 Offended, Castiel produces his Angel Blade; but, Cain says, "Sorry, Castiel. You're not on my list."
And vanishes.



Rowena strolls a corridor with Crowley reflecting on the long day and proposing a "wee idea."
She wants revenge on Olivette, "a high ranking member of the Grand Coven." Olivette led the charge against
Rowena and now that she's back in the States, Rowena wants Crowley to help.
Crowley advises Rowena that when running a con, she should "let more than a few hours of suspicious,
entirely uncharacteristic usefulness pass before making your ask."
Rowena laughs. Of course she's "manipulating." That's who they are.
"My wee sausage, what matter is it that I had a motive? We had fun today, didn't we?"
Crowley agrees it was "fine."
There could be more fun. "Get out of this dump, a break from these foul-smelling suck-ups...
in the process take out a miserable, old witch who's been standing in my way for centuries. What do you say?"
Crowley turns away.



In the bunker, Cas fills them in. Sam verifies the wiping out of the Tolliver family.
Scrolling, he becomes upset. "Damn It." Tommy had a son, "Austin Reynolds, 12,"
living in Ohio and updating his status. Cas knows Cain will kill a kid. Dean starts to move.
They know where Cain will be going. Dean will "do what I have to do. I'll kill Cain."



Dean's packing arms. "When he gave me the Mark, Cain said this day would come,
that after I killed Abaddon, I would have to come and put him down."
Sam's not crazy about the idea as it requires Dean use the Blade
and "win or lose, you may never come back from that fight."
Dean knows this.
Rowena explains her siege plan for Olivette including messing with her head by using
"Rune of Amaranth." Crowley's declares it's "smart." The phone rings and it's 'Not Moose.'
Dean gets to it, "Cain's back. He's gone dark, and I need the Blade."
Crowley wants a motive for helping Dean out.
Dean gives him one: "Cain has a kill list, and you're on it. What do you say, Crowley? You in?"
Crowley interrupts Rowena's plotting. "Something's come up. Olivette can wait."
He retrieves the Blade.


Rowena guesses he's taking it to the "Winchester boy.
You'd give that to the one person who can harness its power against you.  He's a threat to you!"
But, Crowley has a bigger threat and a "common enemy."
Rowena warns him that "consorting with Hunters" is a "threat to his credibility. You honestly believe that
they're your friends, that they care about you?"
Crowley's bringing it.


Outside the Reynold's barn, Castiel confirms that Austin's playing basketball.
(All together! We're part of the team. It's a little tall for my usual perspective but we're in the loop.)
Sam objects to using the child as bait. Dean and Cas are convinced it's necessary. Sam "can't believe what" he's hearing.
"Neither can I." Crowley agrees, joining them. He doesn't care about the kid; he's concerned about the risk to "us."
Dean corrects him, "You're here for one reason. That's to hand me the Blade."
Crowley feels he should keep it until absolutely necessary. They keep strategizing.
(We're banished and miss the rest of the plan.)



Sam wonders what will happen when they "capture Cain." Dean says they'll "cross that bridge if they come to it.
You know last week, when I said that I would go down swinging when the time came? I meant that I was at peace with that. I just
didn't realize the time would come so soon, you know, like right now. I'm scared, Sam."
(Dean's scared? We're terrified!)



Austin walks out of the barn carrying a basketball. He stops, removing his earbuds,
"Someone there?" He turns around to see Cain. "Hello, Austin."
Cain tells the boy he's there to kill him. He pulls out his knife but Castiel intervenes telling Austin to run. 
Cain warns Castiel that he can't stop him.
Cas raises his glowing hand but Cain flicks the angel blade out of his possession
and throws Cas through a fenced truck bed.


Sam holds the barn doors closed. Cain cannot enter.
Suddenly, Cain appears behind Austin who pleads, "Don't. Please don't."
Cain looks at Sam and stabs Austin in the stomach. Austin vaporizes into purple smoke.

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Crowley reveals himself. Cain guesses, "Rune of Amaranth?"
"Good eye." Crowley compliments him. "Something I picked up from my mother."
(17th Century Witchcraft saves the day!)
Cain brushes hay away with his boot revealing a devil's trap.
"Oh. Clever. Won't hold me for long, you know."
Sam sneers, "It won't need to."


As they exit Cain briefly sees Dean through the closing barn doors.



Now, it's Dean's turn. Sam would just be a "liability."
Dean's worried "about what he could do to you, or what I could.
Plus, I need you three out here to take out whatever comes out of there.
And I'm serious.
I mean whatever comes out."
Crowley "happily" agrees and turns over the First Blade. "What guarantee do I have that you'll give it back when you're done?"
Dean reminds him, "If I survive and I come out of there and I don't give it back,
you'll all have a much bigger problem on your hands."
Dean goes up the stairs, giving Sam a smirk of false bravado.


Dean steps into the hayloft. Cain lifts his head, "Hello, Dean. At a loss for words, my son? Allow me.
This is the part where you tell me it's not too late and I can lay down arms."
(Must watch again!)


Cain feels Dean's holding back. "What is it, Dean?
Do you think if you hold back just enough, you won't succumb, that you'll leave this
fight the same as you entered?" Cain throws Dean down. "There is no resisting the Mark or the Blade.
He slugs Dean who finds the strength to remind him, "You told me that this day would come.
told me that I would have to kill you."
Cain snarls, "Is that so?" and sends Dean flying through a window.
"I'm afraid you've misunderstood my intentions here, Dean. When your pet angel found my burial
site, I thought about ending him and swatting him like a fly."
Dean starts back towards Cain.
"But, then I thought about you. Your biggest weakness, the thing I noticed the moment I met you,
your courage, your reckless bravado. I let him go, knowing that he would report back to you,
knowing you would bring into battle the one thing that can kill me, the one thing I truly want."


(Watch the execution for the predictions, sound effects of thunder,
and the Blade going in. Amazing Music and choreography.)

(The clip cuts off the Blade 'Thwicking' out, but it does.)


Dean's DESCENT signifies more than walking down stairs. Suicide is heavy on his mind.
He knows now that he needs an executioner to wield the First Blade: 
Crowley accuses him of lying. Dean readily admits the lie and the lie about Crowley being on Cain's list.
Crowley vanishes.

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Sam proudly congratulates his exhausted brother as Dean falls into his arms.


Dean, exhausted, horrified, and devastated, looks over Sam's shoulder and back up.


Although it's unlikely she can leave, Rowena has bags packed.
She tells Crowley how proud she was of him and how disappointed. "I find you, the King of Hell, and not by
luck or accident. You made that happen all by yourself. ... Now do you understand
why it breaks my heart to see what a COLOSSAL NUMB NUT you've become?!
...A sad, bored, wee boy on the throne who'll flop
ass-up the second those Winchesters hunters,
who'd as soon see you dead as have
you to tea, ask you to. You're no king, not anymore.
You're their BITCH!
She thumps her bags down and storms...?


Poor Crowley. It HAS been a long day.


Dean, bruised and bloody, drinks coffee with a steady hand. Sam's hopeful and proud.
"What you did back there, it was incredible. You know, if you can do
that without losing yourself, that's cause for hope, even without a cure."

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Castiel enters and affirms the First Blade is tucked "Somewhere safe."
Dean rises to "go sleep for about four days." Leaving, he pats Castiel's shoulder.

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Castiel asks, "How is he, Sam?" Sam's destroyed, "Cas, Dean's in trouble."






New touches to character (Sam and Rowena's hobbies, Dean admitting fear)
and information make this script a pivotal one. The Mark of Cain is a Blood Lust infection like an addiction.
There is only relapse and remission, or death by the Blade.
Dean's been living Cain's life in reverse. Notably, it alluded to previous scripts.
Remember Dean's wish to "just cut it off"?
The false bravado exhibited by characters, and the phrase "Do it" finally hit home.
More importantly, this script nudged the viewer to think.
Four characters stand before their judges.
Already sentenced to death Tommy waits for his execution in the grey zone of purgatory.
(Possibly worse than the execution itself.)
Does he want to die when he shouts at the prison guard "LET'S DO IT!"? Apparently not.
When his EXECUTIONER shows up, Tommy reveals his former words to be bravado.
Tommy proves HONEST in admitting his crimes. Cain quickly gives him punishment and salvation.
Is it wrong to kill murderers? If we execute murderers, is the grey waiting zone prolonged torture?

Cas tortures a demon who tells the TRUTH and begs to continue his existence.
Cas deceives him into thinking he will be freed and then kills him.
Is it punishment? Salvation? Prevention?
Or is the despicable valueless and no longer needed?
Castiel is an EXECUTIONER.

Crowley hears a Demon guilty of the political crime of wanting democracy and equitable rewards.
Rowena advises Crowley to kill the Demon as a WARNING TO OTHERS.
Is that a good rationale for executions? Crowley orders him EXECUTED immediately.
The Demon executioners do the deed in order to ensure their own existence.
Is Crowley an EXECUTIONER?

Cain's genocide is to rid the world of his poisonous issue. Castiel's aghast.
What's the difference between Cain's actions and what Cas did moments earlier?
Is it the SCALE that offends Cas? Is it the WHO that's being executed?
Dean, Sam and Cas are appalled by Cain's executing "potential criminals." 
Does saving millions of people validate it?
What is the difference between Cain's killing spree and what the Hunters do?
Remember, Dean killing the kitsune leaving her young son in the cruel aftermath? (7.03)
Is age a factor? Is scale? So much grey.

When a criminal confesses to his murders and asks for an execution, should we comply as in the true case of Gary Gilmore?
In The Executioner's Song,* Gilmore wanted to be executed. "LET'S DO IT!" Gilmore said to authorities.
 Cain requests an execution from Dean. "THEN, DO IT!"
Only the First Blade is capable of killing him, wielded in the hands of someone powerful enough to use it.
Cain told Dean, "Promise me, when I call, you use the Blade on me."
Perhaps, it was the only reason he gave Dean the Mark.
Cain has wanted to die forever. His execution of Tommy was a call to Dean.
Tommy was already slated for an execution. During the fight, Cain lies saying he only wants the Blade.
He also does his best to goad Dean into doing the deed.
He uses Dean's empathy, mass killings, and affirms he will keep killing.
He beats Dean into a self-defensive position. He gives Dean every justifiable motive to be an EXECUTIONER.
Still, Dean hesitates. Cain's "THEN, DO IT!" is sincere. He's surprised when Dean disarms him;
but, he also bows his head in submission.

When we execute criminals, do we then become murderers?
If you murder a murderer who wants to be murdered are you a murderer?
Why do we execute criminals? Do we do it as PUNISHMENT?
Do we do it to protect POTENTIAL victims?
Do we do it because they are UNPRODUCTIVE in a good society?
Do we do it as a WARNING to others not to commit crimes?
Or, do we do it because we afraid to object to it?
Should any being have the right and the power to decide?

Terrified and sorrowful, Dean descends.He knows what must be done to stop the Mark's control.
He must entrust the Blade, the only weapon capable of killing him, to someone trustworthy and powerful.
An executioner...Cas.

Dean LIED to Crowley. Cas and Sam DECEIVE Crowley.Cas DECEIVES a Demon.
But the Demons, Tommy, and even Rowena, all tell the TRUTH.
Shouldn't TRUTH stand on the side of Goodness and not Evil?

(Some Questions to ponder while you lie awake at night.)

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1. Poor dazzling Ruth Connell. Her character is INCONSISTENTLY and unbelievably written.
Surely her motive of gaining freedom is enough without having to overthrow some pasta witch.
Surely a 300+ year old witch would have more convincingly devious methods of manipulation.
Offering a solution to 'split the baby' made sense. Belittling Crowley in front of the court did not.
Conceivably, she could amuse the court with an illusion trick and offer the spell to Crowley to help him
defeat the Mark. Why not make herself useful and supportive? When Crowley returns, beaten by his friends,
she should be consoling and supportive, not have a preadolescent hissy fit.
Rather than becoming trustworthy to Crowley, she becomes every adolescent boys' nightmare, "Mommy Dearest."
Is that why she's there? To give adolescent boys angsty nightmares?
When she dramatically thumps her bags, without any real hope of leaving, it looks more like a precursor to a Toss,
rather than a witchy mother with wiles. The Oedipal undertones are icky.
Her dialogue's hilarious. (Many ad- libs) Her presence dynamic....
How about a consistent and worthy character?


2. Cain's dead? Such a phenomenal character....

3. The fight choreography and execution were flawless, realistic and suspenseful.
But, it screamed for 'new' treatment; not a rehash of Star Wars.

4. The teddy bear should have been a baby shoe.

5. Bitch count =1. But, it was a zinger.
Thanks Show Runner for not allowing the "P" word.
(I'm watching you Berens. Don't be saying P---- like it's a bad thing.)





(Can't pronounce your name; but, this is cutting age brilliance.)








Entwined in plot. Character revealing.














Terribly good performances!
Congratulations Timothy Omundson for the epic portrayal of Cain.





Keith Martin (Warden Skieff) was Daniel Blake in 1.19 "Provenance"



Supernatural Wiki
Storify  (Live Tweets, Photos & behind-the-scenes with Jerry Wanek)
Supernaturaldaily GIFS
Indulgy WEDGIF
*The Executioner's Song Norman Mailer




# novi 2015-08-28 14:46
Thanks for another good read. Really one of the best eps in S10 though I never liked that striped shirt Sam was wearing in the beginning. Can't quite agree with you about the
best performance.Tha t is, Timothy was great with his mane and stance, but my vote goes to Jensen who was epic. And I felt so sorry for Crowley. Mark shined throughout the
whole season. I'd say he deserves to be given a special prize for his work in S10, like Jensen deserved one for S9, and Jared for S8.
# JJA 2015-08-28 15:06
One of the best episodes of the season, and of the past few seasons.

Cain would be a great "big bad."
# cheryl42 2015-08-28 15:51
Easily the best episode of the season. It not only had an old school SPN feel to it, but TO and JA were just over the top awesome in that barn. It didn't hit a false note.
Jensen did tease a little at DCcon that we didn't actually see Cain die soooo......
# AlyCat22 2015-08-28 21:50
Great read tho I have to say I don't quite agree on Cas being able to kill Dean with the FirstBlade. It was established without the MOC it is just a bone with teeth. The only thing (outside of Death, tho he never said he could, just that he wouldn't so who knows if it was in Deaths power to do so...) that can destroy a bearer of the MOC is another bearer with the First Blade. Cas even said (pre beat down) in his speech to Dean that he could resist and fight it but eventually he would turn and Cas would have to watch him destroy the world. If Cas thought it was within his abilities to end Dean then why the painting of that scenario?
Barbara Maake
# Barbara Maake 2015-08-29 00:16
I enjoyed your review Wednesday, and I agreed with most of it. I liked this episode a lot, although IMO it was only the 4th or 5th best episode of the season because there were some parts of it that irked me. Like you, I think Rowena was not well-written here, or indeed in any of her episodes until she finally was split up from Crowley. While I loved her in the later episodes, I found her to be quite annoying in virtually all of her scenes with Crowley. What's worse is that her presence had the effect of sucking every iota of life and excitement from Crowley's character. I hated every bit of whiny, mommy-complex Crowley, so the Rowena/Crowley scenes dragged this episode down a bit for me. I also was very disappointed that when Dean confessed to Sam that he was afraid, Sam said.... nothing. REALLY? Sam's role for the entire first half of the season was limited to being endlessly supportive of and encouraging to Dean, but now, when DEAN WINCHESTER admits to being afraid, Sam can't muster a single word or gesture of love or support? Nope, not buying it. I also was puzzled and disappointed that Cain's death occurred off-camera. Are TPTB just hedging their bets in case they decide they want to bring Cain back? Jensen has hinted at that by calling attention to the fact that we didn't see Cain die. I certainly hope that's not the case because I can't think of any credible, logical explanation for why Dean would have spared Cain. But I also can't think of any reason why they wouldn't have showed the death. Maybe they thought they couldn't do it justice, which is almost plausible given that Abaddon's death was one of the most laughably cheesy scenes in recent years. In retrospect, there's one more disappointing aspect to this episode. When Cain said that Dean was living Cain's life in reverse I was puzzled but intrigued. It didn't really make much sense, but I thought maybe it heralded an interesting new twist in the heretofore boring MOC saga. Would Dean really kill Crowley, Cas and Sam in the specified order? Or at least attempt to do so? As it turns out, Cain's warning was just a tease and never amounted to squat.

There was a lot to like in this episode. The opener on death row was riveting. I also enjoyed the scene in Baby between the brothers, as well as the ending scene in the bunker kitchen. But the best part of the episode was Cain. I loved every second of TO's screen time. He portrayed a magnetic, compelling character, and his scenes with Tommy, Cas and Dean were all phenomenal. I wish they had kept him around for at least a few more episodes (assuming he truly is dead).

One final thought: I agree with AlyCat that Cas could never use the First Blade to execute Dean, because I thought it was made clear in First Born that the FB can only effectively be wielded by someone who bears the MOC. On the other hand, since all of the rules/canon pertaining to the MOC are an enormous muddle, for all I know you're right!
# Wednesday 2015-09-04 19:13
Cain seems to be of the opinion that the only thing to defeat him is the First Blade.
He also believes that only someone else with the Mark can wield the Blade which is why he imprints the Mark on Dean.
Each of them have a Mark. Both Marks instill blood thirsty cravings on the wearers.
The Mark is like an insatiable addiction for which there is only "Relapse and Remission."
Cain may have tried to take his own life but the Mark prevented him from doing so.
Cain believed The only solution to escape the torment of the Mark is to infect Dean with the Mark and have Dean become his executioner.
However, Cain is wrong. There is the lifting of the curse as cure factor and of course the intervention of Death.
At this point, is Dean 100% convinced that the Blade could not be used on him? Or, as in the earlier episode (10.9) does he think that Cas could have the power and "could take him out" ?
He did ask Cas previously to "knife me smite me and throw me in the sun" if he had to.
Dean seemed to think that if things got bad he would end himself, or get Cas to do the deed.
But, he is wrong. The Mark won't let him kill himself and even protects Dean from the Book of the Damned, his cure, by convincing Dean that the Book was evil.
He tries to end his life and he can't. The inability to commit suicide becomes increasingly evident to Dean, and to us, in the The Werther Episode.
So, could Cas wield the Blade against him? Is Cas strong enough to hold out against the power of the Mark? At this time, it seemed to be Dean's hope.
The second the Blade makes contact with Dean, even if it is Dean's back, it is no longer "just a bone."
I don't think we know the answer to this one. It was never tried.
However, Cas proves incapable of doing the deed and takes a beating without getting the Blade and at least trying.
Here, when Dean turns the Blade over to Cas, it is with the hope that Cas take this deadly weapon away from him to keep him from doing more harm.
And, does he hope that Cas will be able to use the Blade to stop Mark's bloodlust? Yes. I believe he has that hope.
Thanks everyone for interesting insights.