Thanks. I see what you mean.

Yes the protag is a gangster and a killer, but his wife and daughter love him, and we see why – all this killing is unresolved pain and anger about the death of his son (backstory) which we learn gradually.

The antagonist is only a bad guy to the hero who believes he’s acting justly, but actually to us he’s a good guy – he’s the one who makes the hero see that what he’s doing is wrong.

Opposition to the hero is threefold (as per Truby) so the antag and the hero’s wife and daughter all attack the hero’s fatal flaw – his self-righteousness – his belief that his actions are ‘just’. The antag is the one who proves to the hero they are not.

Perhaps we could identify the hero as ‘grieving’ and the antag as ‘enraged’.

“Intent on executing every known child killer on the register, a grieving vigilante’s entire justice ‘system’ comes under threat when the enraged son of a past victim infiltrates his gang for revenge.”

Good point re. turning the stakes into a positive, which is what happens in the story – he does stop killing – his new moral action after his revelation. The stakes in this case would be his family. If he stops killing, he’ll save 1. His own life 2. His wife from leaving him and 3. his daughter from hating him (and possibly killing herself).

So:

“A grieving vigilante, intent on executing every known child-killer on the register, is forced to face the fact that only if he stops his killing can he save his family when the revenge-obsessed son of a victim infiltrates his gang.”

or

“When the son of a past victim infiltrates his gang for revenge, a grieving vigilante, intent on executing every known child-killer on the register, is forced to face the fact that only if he stops his killing can he save the ones he loves.”