How to end the war after becoming Captain?

[Charlemagne]

I'm playing in the Utopia mode, when the antagonist faction started a civil war at first i wanted to exile them but i managed to pass the law to become the captain but i can't see any way to end the war besides exiling the antagonist faction.

Is that an oversight? Am i locked because of my previous choice?

[It's a Mind Game]

If you are a captain, then in your generator district you should have the action that will reduce fervor of all factions, which should help with managing war. Then (or before that if you want) just click on any district that has fighting in it and use your guards to stop them. Do that in every district and it should end.

[Nirnias]

There should be three choices, exile faction x, exile faction y, or force them to obey you. The last option requires you to start building internment camps for each faction to live in. That choice in Utopia mode didn't surface until 1100+ weeks in to the game.

[lambdoid]

There's an option to reduce their numbers. I can't remember the exact name offhand, but it's in the faction menu. They gradually get dragged off in the middle of the night and 'disappeared'. It takes a long time. I managed to get rid of them all that way.