Let's chill

You can defuse tense near-combat situations with your persuasive words or a performing act.
Performer rapping:
"Why spend the evening cutting our throats,
when we could simply chill out, smoke and enjoy,
don't forget that life's so fucking short,
why should we shorten it even more?"

Dealmaker speaking: "Listen... We could fight now, but what happens next? What happens when the Black Teeth come to raid us? Both parties will be weakened, and neither of those who survive tonight will survive the raids. If we fight now, nobody wins, this settlement will become debris in the dust, and we're all nothing but carrion... and not only us... your families and friends will also become a feast for the vultures, or worst... slaves to the Black Teeth, to be abused and raped for life... So... I strongly advise you to think very carefully your next actions..."

This kind of things only work before the first attack is made.
To do so, you can roll the relevant skill for one of your acts, or a relevant Attribute & Persuasion (usually Charisma).
Any modifiers to the result of your roll are allowed (for example, see Talented). This edge affects all the people involved in the escalating conflict, provided they are able to percieve your act, or hear your words.
Modifiers to the difficutly of the roll come from the relationship between the parties involved in the conflict:

• Previous bad blood: +1.
• Previous open hostility: +2.
• Context of open warfare: +4
• Some assymetry of combat power: +1
• Obvious assymetry of combat power: +2
• Overwhelming assymetry of combat power: +4

The results:

• Critical Failure: You somehow managed to insult both parties. Violence starts immediately and nobody likes you.
• Failure: They ignore you. Life in the Afterfall follows its natural course: Violence.
• Partial Success: Decisive Moment. Your intervention bought some time. Another type of intervention is required, or things will turn ugly very quick.
• Success: Just give us a reason. Swords are sheathed, and unless one of the parties leave, a very tense and fragile situation follows. Situation might re-escalate easily with a bit of external intervention.
• 1 Raise: Everyone is annoyed. The parties are still angry, and either fake to ignore each other, or start suspecting dialogue might actually avoiding quite some trouble.
• 2 Raises: Reluctance. Nobody will admit it since everyone is trying to save face, but perhaps not fighting might have been actually a good decision. Mutual suspicion is still obvious.
• 3 Raises: Let's start over. Parties become truly neutral towards each other. They either truly ignore each other, or they come to their senses and realize dialogue is in their best interest.

Limits:

• This only works at small scale (max. 20 people on each side), a single character cannot stop a full blown battle between two armies armed to their teeth by singing a song in the middle. That would actually get him killed.
• If there is a history or context of enmity between both parties, whatever measure of peace is gained with this edge can only be guaranteed to be sustained for the scene (a night at the bar, for example), especially if only small groups of larger conflicting factions are involved. The intervention could ge
• This only works when violence is about to start immediately. Hence, it doesn't work in the context of full scale warfare negotiations, in which leaders won't kill each other immediately, but they will rather send their armies to slaughter afterwards.