Nightwing Kills Victor Zsasz (Injustice Gods Among Us)
Personally, I agree heroes shouldn’t kill. But there are truly some twisted individuals like Zsasz who simply can’t be rehabilitated or locked up. The only permanent solution to completely stop them is to kill them. Now if Damian here gave Zsasz a knife to make it an even fight, it would have been better. But really, no complaints about Zsasz being killed in all of the DC universes.