Green Arrow did use lethal force in the past look at the Mike Grell stuff. If a character does something once he can do it again. 

I've always thought the concept of an archer not using lethal force to fight crime slightly odd. To shoot an arrow at someone you should be prepared to kill. Unless we're talking 70s trick arrows of course! ;o)

Looks like he's doing it right.

Prometheus' helmet shouldn't has stopped this arrow ? 
As far as I am concerned, I think a guy who is fast enough to take down the whole JLA (well, the one in Cry for justice) and to stop a kryptonian, would be able to catch/deflect an arrow ? 
Do you think that, when his body will be found, heroes will immediatly understand what happened ? 
_"Hey guys, prometheus is dead ! "
_"Really ? How did it happen ? "
_"it seems rather obvious : He has a green arrow stuck in his brain ! "
_"My god, who could have done something like that ?"  
 
Prometheus is a mad man who killed thousands people. He clearly didn't want to stop any time soon. It is normal that one of these heroes finally killed him.   The only other mean would have been to do the same thing than J'onn did.
The scariest thing about Ollie is that he knew that he would kill him when he made his speech (in order to convince the jla to release him).

FINALLY. Batman should be taking notes.

I love that he killed Prometheus!

Batman killing a villain isn't batman (except in keaton movies... and early comics ). 

Who else thinks Prometheus gonna come back to life and make Green Arrow pay of killing him?

Wonder Woman killed someone years ago and everyone got over it.  I really don't see the big deal with Green Arrow.  Just like the guy Wonder Woman killed there was really no other way.  The League will be pissed, but they'll get over it eventually, and then we'll find out it really wasn't Prometheus, and Green Arrow was coaxed somehow.  Even if he's not, they'll get over it

Frankly, I applaud Green Arrow for not taking the Batman/Superman approach to villains whose sole purpose in life is to cause death and destruction on a massive scale.  Those two could learn loads about justice from GA and Wonder Woman in ending threats.

Green arrow's arrow just turned Red  : )

"there was also the death of a character that we all know."    Who got killed?   
  
Green Arrow felt to me he was very intense and hime putting a Arrow into dudes head isnt suprising.

 You know in the real world such acts of vengeance would not be tolerated in the judicial system.  Green Arrow would probably face a trial and imprisonment in the real world.  But in a world where people display incredible abilities and skill and powers, real world law enforcement and the judicial system would basically be ineffective.  Most likely your average police officer is not going to be able to take on a villain such as Prometheus.  So, in the comic book fantasy world it would come down to how much force does a hero need to use to stop a villain and could it not be sanctioned by the government?  The heroes in the comic book world have been trained to take on such threats so should they not go all the way for the sake of justice?  Possibly.  It is a shame though to see such classic characters like Green Arrow and Wonder Woman have to resort to such violence.  It's a shame all together that comic books now include so much gratuitous violence and killing.  (For example Blue Beetle?  Ares?  Ultimate Wasp?  Just to name a few.)  Overall this brings up a thought, maybe it's time to go back to telling good fantasy stories where the good guys always win and evil is vanquished.

I say good job and then a standing "golf clap"

Looks like Green Arrow just looked "Watchmen".

" Wonder Woman killed someone years ago and everyone got over it.  I really don't see the big deal with Green Arrow.  Just like the guy Wonder Woman killed there was really no other way.  The League will be pissed, but they'll get over it eventually, and then we'll find out it really wasn't Prometheus, and Green Arrow was coaxed somehow.  Even if he's not, they'll get over it "

Why is it always Green Arrow? Can't he manage his anger issues?  Sure it was his ex-side kick, But you did not see Batman throttle the life out of Joker for Killing Jason. Well he was pretty close to killing Joker in Batman: Hush, when Joker shot the clayface Tommy Elliot.  Villains (like Prometheus) want to make sure that they did the worse thing that they can possibly do, So that they can no longer be a joke. I guess He picked the wrong person to terrorize. Maybe If he killed Damian, or Would Dick just go out and try to kill him(Maybe not). Besides Roy gets that cyborg arm right? So Oliver goes out to kill Prometheus over an arm thats not even his? 

"Why is it always Green Arrow? Can't he manage his anger issues?  Sure it was his ex-side kick, But you did not see Batman throttle the life out of Joker for Killing Jason. Well he was pretty close to killing Joker in Batman: Hush, when Joker shot the clayface Tommy Elliot.  Villains (like Prometheus) want to make sure that they did the worse thing that they can possibly do, So that they can no longer be a joke. I guess He picked the wrong person to terrorize. Maybe If he killed Damian, or Would Dick just go out and try to kill him(Maybe not). Besides Roy gets that cyborg arm. So Oliver goes out to kill Prometheus over an arm thats not even his?  "

Are we building towards a more Justice Lords or Ape Vengers theme here, If they don't stop, kill them?

"

SPOILER WARNING: Click here to reveal hidden content.

They killed his granddaughter.

 Hell yeah it was justified  "

looks coool!!! 
 
 
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http://easy-cgc.blogspot.com/

I loved how radical Arrow has gone. He is definately that true blue father, you hurt his kids he will make you pay. And he did, and I find it alright an fine what he did. That bastard hurt his kid and grandkid, so he had to pay. Its what I would have done.

JUSTICE!
 
When he put that arrow in Prometheus's face, I literally fistpumped.

Green Arrow got lucky

" Green Arrow got lucky "

" @Son_of_Magnus said:

" Green Arrow got lucky "

Green Arrow never gets lucky...  Unless it's with your momma'. "

They always say in comics to the hero "once you kill you can never go back" but isn't that a double standard for all the villains that reform? How come they get a second chance after all th good they've done? I've always wondered how writers never realised how stupid that sounds.  
 
 As for Ollie killing...well I hope this leads to a permanent character change. I don't want him just killing once villain saying his sorry sulking for a few months then everything being back the way it was. Maybe make it so Ollie become the wolverine/punisher of DC, the one willing to go that bit further but keeping in line with his character show how it absolutely destroys his mental well being. Would make for an interesting run. 
 
Thing is though, comics are meant to inspire. Punisher killing people makes sense because there's nothing inspiring about a big dude all in black with big guns. But Ollie's they type of character designed as a symbol, same as superman.  
I'm a bit split on the issue, I don't know whether this is a good thing or a bad thing. I just hope there's some commitment and it's not just done for shock value and forgotten in a few months. 
 
 PS do you think they've followed Smallville GL seeing as he killed Lex a few seasons back??

but the problem is that heroes do kill they almost have to if you want to stop evil evil must be destroyed......
look at Secrect invasion i am sure that thor and iron man killed hundreds of skrulls and they are noble heroes does anyone care? Batman kill the ultimate evil darkseed? does anyone care? and look at guys like green arrow and wolverine lets be real despite how you feel about their skills fighting these guys should only result in death..........i mean what else is an arrow gonna do other than kill you? what else is 3 blades on a fist gonna do other than kill you? heroes who wield weapon of death are gonna cause death......and if they dont then WTF?

I think it falls within the context. Green Arrow wasn't always mr. goody two-shoes. His son was mamed, his city was leveled, and his granddaughter crushed. It makes perfect sense for Ollie to do what he did. It would be harder to sell if it was Mon-El, for example, who seems to take the moral high ground that Superman stood for. But it's completely believable that someone like Arrow would go to such lengths. He's more complex than a simple black-and-white outlook on things.

 
My hope is that they continue with this and remain consistent. If this was a one-time thing, it's pretty useless. But if they follow up on it, or if Green Arrow takes a more lethal approach on things from now on, the killing of Prometheus served a greater purpose for the character. He can become an in betweener as he can be a hero and a sort of villain at the same time by having certain heroes not condone his behavior and choose to do something about it (I guess like Punisher, but with arrows).

after what Prometheous did to the Green Arrow family, Ollie is excused to do whatever he needs to do....I just feel bad for Roy...he hasn't woke up yet and doesn't know that he not only lost his arm but his daughter died to

   As some of you already pointed out Green Arrow has had a violent past, the Longbow Hunter's being the best example. He's also been more aggressive than batman, I mean the guy doesn't use trick arrows anymore, when he shots someone he's hitting them with real fricking arrow. But, I think the most important part of all this is that Green Arrow is suppose to be the imperfect hero. 
        I kind of see him as the everyman batman; sure he's clever, skilled, and all that but, he's also more flawed and that makes him more relatable. The big reveal at the end of The Archer's Quest was that he knew about his son's birth and left him, he regrets it like nothing else, but he still did it. I think moments like that make him a more interesting character, the hero that doesn't always do the right thing. It puts him in contrast to Superman and Batman who are almost perfect, and have a very staunch sense of justice, Ollie's a bit more human he let's his emotions get the best of him.

didn't hawkeye go through the exact same thing? ended up killing wanda after finding out she did some screwed up stuff in the marvel universe that incorporated everyone in the avengers

This is such a horrible defecation on the character of Green Arrow.
 
Wake me when its rebooted out of continuity

"    As some of you already pointed out Green Arrow has had a violent past, the Longbow Hunter's being the best example. He's also been more aggressive than batman, I mean the guy doesn't use trick arrows anymore, when he shots someone he's hitting them with real fricking arrow. But, I think the most important part of all this is that Green Arrow is suppose to be the imperfect hero.         I kind of see him as the everyman batman; sure he's clever, skilled, and all that but, he's also more flawed and that makes him more relatable. The big reveal at the end of The Archer's Quest was that he knew about his son's birth and left him, he regrets it like nothing else, but he still did it. I think moments like that make him a more interesting character, the hero that doesn't always do the right thing. It puts him in contrast to Superman and Batman who are almost perfect, and have a very staunch sense of justice, Ollie's a bit more human he let's his emotions get the best of him. "

" This is such a horrible defecation on the character of Green Arrow.  Wake me when its rebooted out of continuity "

" Wonder Woman killed someone years ago and everyone got over it.  I really don't see the big deal with Green Arrow.  Just like the guy Wonder Woman killed there was really no other way.  The League will be pissed, but they'll get over it eventually, and then we'll find out it really wasn't Prometheus, and Green Arrow was coaxed somehow.  Even if he's not, they'll get over it "

I've seen a few people mention Roy and how he might take this, but what about Cheshire?  Lian was her daughter as well and you can't say she doesn't love her. 
 
Also, i think Green Arrow was justified in what he did, but this needs to have ramifications, like it did with Ultimate Hawkeye when he killed Black Widow.

Ollie is absolutely justified in what he did. Prometheus attacked his family. He attacked Roy, whose practically Ollie's son, and he killed his granddaughter. Ollie is human and he's entitled to go through the motions. Prometheus deserved to die. My only qualm is that Roy won't be the one to take down the man responsible for....what happened to Lian. So yeah.