When Obi-Wan defeats Vader on Mustafar, he leaves Vader alive. Sure, he's missing his legs and has just caught on fire; but when Obi-Wan walks away, Vader is still alive.

I think it's likely that Obi-Wan would have sensed that Vader was still alive until he was a fair distance away from Mustafar, saving Padme.

In addition, we have this line, from Obi-Wan to Vader:

You were the chosen one! It was said that you would destroy the Sith, not join them. You were to bring balance to the force, not leave it in darkness.

So Obi-Wan knew that Anakin was now a Sith. He also seems to hold no hope (at that moment) that Anakin could fulfill the prophecy in the manner in which the Jedi believed he would. It's as if he gave up on Anakin and the prophecy right there.

But he had him! He freaking had him and he let him go! Why not finish him off? All he had to do was walk up and take off his head.

Maybe he didn't want to kill a defenceless man. In that case, why not arrest him to be tried by what was left of the Jedi (Yoda and Obi)? Why just leave him there?

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    I always found it odd... I wouldn't think Obi-wan would've killed him out of anger, ... that's not the Jedi way. BUT - if as Obi-wan said, he "loved Anakin as a brother"... I would think he would be merciful and put Anakin out of his pain and misery as he lay there burning to a crisp. That is I would've expected him to kill Anakin, but not out of anger or revenge, but rather out of mercy.
    – eidylon
    Commented Feb 17, 2012 at 3:25
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    Or even because he was too dangerous to be kept alive? Mace Windu says this about Sidious; it's not too far a stretch for Obi-Wan to believe this about Vader as well.
    – Anthony
    Commented Feb 17, 2012 at 3:28
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    Or to take Anakin and stick him in a kolto or bacta tank, rather than leave him there to die an agonizing death. Unless Obi-wan sensed that Palpatine was on the way and he didn't have time to carry Anakin to the ship.
    – Xantec
    Commented Feb 17, 2012 at 3:31
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    "Sure, he's missing his legs and has just caught on fire" - a thousand upvotes are due to you. Commented Mar 5, 2013 at 15:14
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    It's one of my least favorite scenes in the entirety of Star Wars. First, the lousy dialogue. Second, the lame "higher ground" bit. But finally, Obi Wan leaves his supposed "brother" to die in agony as opposed to trying to either save him or put him out of his misery. The scene clearly indicates Anakin is still alive as Obi Wan walks away - he is screaming in pain. It's a moment of incredible cruelty for a supposed Jedi.
    – joshbirk
    Commented Apr 13, 2014 at 15:25

12 Answers 12


Anakin was Obi-Wan's best friend, student and a war buddy who saved his life many times. NOT someone you would be terribly interested in offing.

If you recall the fight, he tried to TALK Anakin off of jumping him from a disadvantageous position which resulted in him being all cut up:

OBI-WAN: It's over, Anakin. I have the high ground.

ANAKIN: You underestimate my power!

OBI-WAN: Don't try it.

And later:

OBI-WAN: You were my brother, Anakin. I loved you. [leaves]

So, he didn't wish for Anakin's death.

As far as "saving" Anakin from burning, it didn't appear as if there was any possibility of that:

OBI-WAN looks in horror as ANAKIN becomes engulfed in flames. OBI-WAN can't watch him as he struggles to climb the embankment, covered in flames.

Obi-Wan reasonably assumed that Anakin was already dead/irreversibly dying.


To address the "Why not finish him off" - this was answered in Matthew Stover's "Revenge of the Sith" novelization: First, because he had no time due to Darth Sidious prompt arrival. Second, because it was not the Jedi way.

Obi-Wan looked down. It would be a mercy to kill him.

He was not feeling merciful.

He was feeling calm, and clear, and he knew that to climb down to that black beach might cost him more time than he had.

Another Sith Lord approached.

In the end, there was only one choice. It was a choice he had made many years before, when he had passed his trials of Jedi Knighthood, and sworn himself to the Jedi forever. In the end, he was still Obi-Wan Kenobi, and he was still a Jedi, and he would not murder a helpless man.

He would leave it to the will of the Force.

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    @anthony-arnold: And who would Obi-Wan turn him in to? The Republic is gone; it's become the Empire, which would consider Obi-wan the criminal and not Vader. It's pretty much either kill him, or hope the lava does.
    – KeithS
    Commented Feb 17, 2012 at 1:10
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    "It's over, Hayden. I've got the high ground, just like Darth Maul did in Episode 1 right before I killed him successfully. Ignoring that, if you jump over to me, I will cut your shit off." --GeeksOn Abridged Episode 3. Commented Feb 17, 2012 at 1:14
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    Still, as a former best friend, he could have killed him out of mercy if he believed he will inevitably die.
    – vsz
    Commented Feb 17, 2012 at 7:22
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    I believe it is said somewhere in an ebook that OB1 feared to fall to the Dark Side should he finish Anakin.
    – user8252
    Commented Jan 5, 2013 at 6:22
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    If climbing back down to the "beach" would take too long, why not a little Force push back to the "river"?
    – KSmarts
    Commented Jan 23, 2015 at 22:26

You seem to forget (though you said it yourself) that Vader was close enough to the lava river to catch on fire. It's amazing (implausible really) that both of them didn't burst into flame half a dozen times during the duel, but nevertheless it's reasonable to assume that first, Obi-Wan wouldn't have been able to withstand the heat of approaching Vader to deliver the coup de grace, and second, he didn't put very high odds on a one-armed, no-legged Vader burned within an inch of his life being able to get himself out of danger. Finally, yes, as a Jedi Obi-Wan is more or less a policeman. He has stopped Vader from being an immediate threat, and while there's no legitimate authority to turn him over to, killing a "prisoner", especially out of anger for what he's done, is just not on. Remember WAY back at the beginning, Anakin disarms Dooku (literally) and has him at his mercy, but balks at the thought of actually killing him.

Out-of-universe, we know Vader survives. He has to; the next three movies make no sense if Vader dies on Mustafar. So, Obi-Wan can't kill him. Whatever machination the script-writers needed to get Vader so badly disfigured he couldn't live outside his suit, but NOT kill him, was the order of the day.

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    What about moving him with the force?
    – Anthony
    Commented Feb 17, 2012 at 1:13
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    Anakin was beyond saving, either physically or mentally/spiritually. Only Vader was left. Obi-Wan either couldn't bring himself to destroy what was left of his former friend, or simply assumed the lava and fire would do its job (Vader was sliding down the gravel slope toward the lava the whole time they stared each other down). By the time Obi-Wan would have known Vader didn't die, it would have been too late to do anything about it.
    – KeithS
    Commented Feb 17, 2012 at 1:40
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    One more thing, more practical; the G-canon doesn't ever show "Force Pull" IIRC. People are pushed directly away, choked with their feet on the ground, etc, but never lifted off their feet (possibly excepting Padme; I can't remember if she's lifted off the ground) or pulled toward the Force user. In G-canon, levitation by the Force only happens on inanimate objects or the Force user themselves to augment leaps. Even in Extended Universe, levitation of a living thing is almost always through the Dark power, Force Choke.
    – KeithS
    Commented Feb 17, 2012 at 1:45
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    Well what about force pushing him into the lava to at least make it quick?
    – Zommuter
    Commented Jul 1, 2013 at 12:33
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    Whatever machination the script-writers needed to get Vader so badly disfigured he couldn't live outside his suit, but NOT kill him, was the order of the day. It would've made so much more sense if Palpatine had arrived with his clones right at the end of the fight (as Vader is scrabbling up the hill and after Obi-Wan has had his little cry-fest) to "scare" Obi-Wan off. Then this whole discussion would be moot. Commented Jul 31, 2014 at 18:17

This has parallels in two earlier scenes in Episode 3 (both quotes sourced from IMSDB), first one when Anakin dis-arms (and dis-hands) Dooku, then kills him:

ANAKIN: ... I couldn't stop myself.

PALPATINE: You did well, Anakin. He was too dangerous to be kept alive.

ANAKIN drops COUNT DOOKU's lightsaber, moving to PALPATINE.

ANAKIN: Yes, but he was an unarmed prisoner.

ANAKIN raises his hands toward PALPATINE, who is strapped in the Admiral's Chair. The Chancellor's restraints pop loose.

ANAKIN: (continuing) I shouldn't have done that, Chancellor. It's not the Jedi way.

And the second one just before Anakin's fall to the Dark Side:

MACE WINDU: You Sith disease. I am going to end this once and for all.

ANAKIN: You can't kill him, Master. He must stand trial.

MACE WINDU: He has too much control of the Senate and the Courts. He is too dangerous to be kept alive.

PALPATINE: I'm too weak. Don't kill me. Please.

ANAKIN: It is not the Jedi way...

In both cases I've emphasised Anakin himself noting that killing a disarmed prisoner, however evil that prisoner may be (even a Sith Lord - note that both cases also have "too dangerous to be kept alive") is not the Jedi way.

The answer then becomes simple: Obi Wan didn't finish off Anakin because to finish him off would be not the Jedi way.

  • 6
    I like this answer, and upvoted it, but have to point out that Mace Windu, Jedi Master and member of the Jedi High Council, certainly has a better and deeper understanding of what the Jedi way is than Anakin, who had only been granted the title of Jedi Knight 3 years prior, and who was literally moments away from completing his transition to the Dark Side.
    – Beofett
    Commented Jul 31, 2014 at 12:57
  • @Beofett true, but it seems like all jedis have different understandings of the jedi way. It makes sense that the reason Anakin believes it's not the jedi way is because he was trained by Obi-Wan. Commented Jun 21, 2017 at 14:57

In the Stover novel Obi Wan said (or thought): "It would be mercy to kill him, and Obi Wan was not feeling mercifully". It also mentions that Obi Wan still remembered that he was a Jedi and Jedi don't kill unarmed people, so Obi Wan left it to the force.

  • 11
    “Jedi don't kill unarmed people” — and Anakin didn’t have any arms left! Arf! That should have been a line of dialogue. Commented Aug 1, 2014 at 9:27

He was confident that Vader was dying, but didn't want to finish him off. Even after, he was sure that Vader had died. It was only until later that he was informed otherwise. He hadn't anticipated the Emperor saving him.


Obi-Wan was already sickened over how the confrontation with Vader had gone. He couldn't bring himself to administer the coup d'grace, and likely assumed that Vader was mortally wounded anyway. He also had to get back to the ship and get Padme to a doctor right away.


I think Obi Wan could not bring his heart by killing Anakin.. So he left the lava do his job.. He actually found out later that Vader survived, during the battle of Kashyyk


I think that obi wan did not want to kill Vader, so that he (Vader) could fulfill the prophecy, and finally be rid of the sith. Which he does eventually do.


I always thought that Obi Wan looked at Vader as not being Anakin anymore, Anakin was gone for good and the dark side now had Darth Vader. The betrayal of Anakin, the killing of the children and then possibly Padme, had Obi Wan devastated. I think he walked away because he too felt defeated and killing a already tortured body was too much after all that happened. Obi Wan did not seem to me as somebody that added salt on a open wound. The damage was done and killing Vader was pointless. Vader was beyond saving in more ways than one.

  • 2
    "I always thought" it not a convincing way to begin a fact-based answer. These are opinions that would be better suited as comments, not as answers. Commented Jan 12, 2014 at 7:59
  • @Meat: YOUR comment does begin with "I always thought"...
    – yrodro
    Commented Nov 13, 2014 at 3:30

I actually interpreted it as Kenobi for a short moment succumbing to his own darkness. All of his anger, his frustration, his pain from Anakin's betrayal resulted in him letting Anakin suffer and die a slow death, instead of finishing him off and giving him a quick painless end. After all, it was only through Anakin's incredible power in the force and the timely arrival of Palpatine did Anakin survive. I imagine the character of Kenobi thinking he left Anakin to die in agony as payment for all of the suffering he has caused. Afterall, if you chop off someones legs and one arm, and then they burn from head to stump, you think not only are they in unbelievable pain, but they are going to be dead very very soon.


He does not need to kill Anakin at this time

He's cut off his legs. He's taken an arm. Vader still is very strong but he's much weaker without the force he was storing in his limbs. The prophesied super Jedi will not become the most powerful Sith in the galaxy. Indeed, Palpatine acts swiftly.

He makes sure the healing is painful, the suit is ill fitting, because now Anakin no longer is a threat to him. Indeed, he is a loyal servant, much like Dooku was. He's still terrifying, but crucially, not to Palpatine, who can now relax and send his new dog to fetch and kill on command.

Anakin would not have needed Luke's help to free himself of Palpatine, although, it is by no means certain that Anakin can actually dethrone this creature.

Painful as it is, there is justice here: Obi-wan is partially culpable for this state of affairs. Qui-Jon probably would have been a better master for Anakin. Alas, he was slain, and perhaps that is part of the reason Darth Maul was dispatched: To deprive the Chosen One of an experienced master, one who would see what was happening before he knocked up Padme, possibly sparing both of their lives.


My plain answer is that Anakin was wearing plot armor. How plot armor is used in stories

  • 1
    Beware! TV Tropes link!
    – user8719
    Commented Apr 12, 2013 at 19:09
  • This really is the only answer that comes close to making sense. The prequels are fun, but there's no sensible in-universe explanation for not just Force-hefting the guy a few feet back and finishing Gollum's work.
    – krs013
    Commented Dec 6, 2015 at 10:39

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