User blog comment:Jamie/Episode 14 - When Heroes Kill/@comment-166-20140707114656/@comment-6548012-20140707170926

Well, I think that when you take killings like the death of Uatu in Original Sin, that's completely not [forgivable], obviously.

But when you take the Joker in Batman: The Dark Knight Returns, well, did you count the people he killed, the damage he's done ? Because that really is a lot, I know that Ellen Yindel considered Batman as a murderer after this, but it's because she just hated Batman since the beginning.

For a better example, we should take the example of Wolverine, killing the Hulk in Old Man Logan Giant-Size. After all, Hulk's gang is murderous and rampaging. It makes its own law in the whole west coast. But they are the rulers of this part of the USA, so if they're no more, it falls into anarchy, "and thou mourn when thy flesh and thy body are consumed", y'know. It might be justified because the gang killed Logan's family, but still, it is not the Hulk gang's fault if everything became like that. After all, in the same reality, Wolverine killed the X-Men; and he was never forgiven.

So, some killings might be justified and/or forgivable, but some can't be. And some others, are more complex, to explain those, it would take days.