This would generally be the Last Case Scenario to prevent complications in our RP as formation of many factions which causes management problems.
A sub-faction general must have the support of at least two allied faction generals / Another Faction Leader's Support to start a Civil War. The two allied generals will become a part of that sub-faction.
If a Civil War Breaks out, then it must be announced in the World Events Board by a thread by the Sub-Faction Leader.
All counter-Announcements and announcements must be posted in that thread for consistency.
For the Duration of the Civil War, a separate Temporary Faction section will be made for the Sub-Faction where all discussions will take place. The Sub-Faction Board will be placed in the Civil War Command Centre
Possible Win/Loss Scenarios :-
If the Sub-Faction wins, then it can choose to either stay with the main faction and overthrow it . Essentially the Sub-Faction Leader becomes the Main Faction Leader or it might join another faction. The temporary Section contents will be merged/Archived in the main Faction's Board.
If the Sub-Faction loses, it will became a part of the main Faction and will not be able to cause any more civil wars, i.e; the main faction Leader's command will be absolute.