If (New 52) Batman killed (New 52) Joker in the Bat Mobile after a series of events lead him to do it and then later, turned himself in unmasked, what would your reaction(s) be? And for that matter, what would the Bat Family's reactions be if they knew what happened?
I think it would be an interesting series of events.
In my opinion, the bat family would be supportive of him and would keep up the work which he wold be unable to do from prison. All the Robin’s and Batgirl’s would be brought closer due to his absence, despite their differences they always had the Bat and without him there would be a massive hole in their worlds. Maybe one of them will take up the hood, but I highly doubt.
We’d also have the League and their reactions, tears, support, public press release, one of the more interesting visitor days at Blackgate. But also the disappointment that Batman broke his one creed, even if it was the Joker.
Then there would also be the reaction from Gotham, the joy at the Joker finally being gone forever, but the sadness that so to has the Batman, There would be the surprise at Mr Wayne’s revelation, and of course the sad, knowing, smile of a certain Police Commissioner. In the aftermath groups who idolize Mistah J would riot at his murder, at a city that would condone such actions, and at the Bats who did it.
Then there would be the reactions of the villains. I think it would be a strange eclectic mix of despair and elation, and many, such as the Court of Owls, would be pleased at the result and may try to recruit Wayne and his new found killing side.
And also, they the whole shebang about whether joker is dead in the first place. If he actually stays dead or if that whole shtick about the immortal pale man comes into play and the lazurus fluids bring him back to torment his fallen foe, as even in death he still gets the last laugh, he made batman kill.
Finally, my own opinion of such a turn of events would be grateful curiosity. There’s always the argument against Batman’s reluctance to kill, and many cite the Joker as the perfect subject to bend the rules a little. In most cases when he does stop the maddening laughter it’s as the final part of an arc, a nice bow to wrap up the story. I can only think of a few cases where it isn’t, which is the days of Injustice: Gods Among Us, but in that Bruce took the fall for Superman in the hope to keep Clark’s untarnished reputation (and it was a dream), and in the Arkham game/comics where the Arkham Knight (among other things) spring up. So, to have a story within the main continuity would be a great exploration of the character and his reliance on his polar opposite, and would be a study of the immortality of the Joker, as a villain, as a man, and as a nightmare.