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Map Painter (edit your campaign map using tww2-map-painter)

With this mod, you can edit region ownership using
https://imrz.github.io/tww2-map-painter/
and then load that edited map ingame when starting a new campaign.

Check out the Steam guide made by Bombardier. And check out his Web campaign editor mod that is the successor of this mod.

Make your edits to the map, and then click on Export to the right and save that file as "map.json" and put it inside your "steamapps\common\Total War WARHAMMER II" folder.
Then once you start a new campaign use the button on the top left (see first screenshot) to load that map.

I added an "export map" command to my console mod, so you can now upload your ingame map state into the app. "export map" will create a map_out.json in your WH2 Steam folder.
https://steamcommunity.com/sharedfiles/filedetails/?id=2094338970
With OvN you can start a campaign, export the map ingame, import into the app and make changes, export in the app, and load it ingame. This will preserve the regions for custom factions.
Giving regions to horde factions won't work.

Works on both Vortex and Mortal Empires maps. And note that although the app lists all factions on both maps, you can't just add ME faction to the Vortex.
If you take away a region from a faction any armies of that faction in that region get moved to another region they own. So move your armies into regions you own before changing the map, or they'll stay in place.
If a faction doesn't own any regions at all their armies get deleted.

Script mod = compatible with everything. Should work in MP (both players need to put the same map.json file inside their WH2 folder) but need someone to test. (A comment said it desynced for them they can share the save file after changing the map.)
Note that by default in tww-interactive-map Malus doesn't start on the Dragon Isles, same for other conditional starts like Grom that depend if they're player controlled.

Check out my other mods.
Thanks to IMRZ for making the tww-interactive-map app, it's not mine, some comments think it is.

If you can't see the button ingame when you start a new campaign the most likely cause is your ingame scripts are broken because some other mod you have has a script error and that makes other script mods stop working as well. Try this mod by itself to make sure.

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