I can't figure out how to delete a custom faction from within the UI. If I create a custom faction, it appears the next time I start a new game, but unlike a custom Soverign, for which right-clicking brings up an option to delete, there's no obvious way to delete a custom faction.
As a workaround, I can go into My Games/Elemental/Races and delete the file, but it seems like this should be in the GUI...