Factions are 8000 rupies to create. To increase your faction power you must stay alive, and ensure your members do the same.
Relations, Territory and War
The factions on the server have relations to each other. They can be ally, neutral or enemy. You choose your wished relation to another faction through a chat command.
If both factions wishes ally you will be allies.
If one faction wishes enemy you will be enemies.
You can never hurt members or allies (friendly fire is always off).
You can not hurt neutrals in their own territory.
You can always hurt enemies and players without faction.
Damage from enemies is reduced by a certain percentage in your own territory.
Only faction members can build and destroy in their own territory. Interaction with the following items is also restricted by default: Wooden Door, Trapdoor, Chest, Furnace, Dispenser, and Diode. Make sure to put pressure plates in front of doors for your guest visitors. Otherwise they can’t get through. You can also use this to create member only areas. As dispensers are protected you can create traps without worrying about those arrows getting stolen.
Every player has “power”. The power can at most be 10 and at least be -10. If you die you lose 2 power. Note that it doesn’t matter at all how you die. You can be killed by an enemy or drown in sand. In either case you will lose 2 power. The power will be restored over time, but only while the player is online; while offline, their power will not regenerate. It takes 5 min for 1 power to be restored while online. You will also lose 1 power for every 24 hours offline. Note that these values are all just the defaults, and can be changed as desired.
The power of a faction is the sum of all member power. Every power grants the faction right to claim one land/chunk. You can claim land from a faction if it has to low power.
A faction with two healthy players, MrApe and MrCow, had a faction named SuperAnimals. The faction SuperAnimals had 20 power. This was because the members had 10 power each and 10+10 is 20. They claimed as much territory as they could (20 minecraft chunks that is). Then MrApe went and drowned in lava. As MrApe died he lost 2 power. After that he had only 8 / 10 power and the faction SuperAnimals had 18 power as 8 + 10 = 18. At this time SuperAnimals had more land than they could handle (20/18). Then their enemy Bulldozer took the chance to claim some of their land. He managed to claim 2 chunks at the border of their territory. Then he could not claim more as SuperAnimals now had (18/18) land.
Note that if you claim land from another faction you must start at the border of their territory.
The server admins can create safe zones. These zones can not be claimed by other factions. PVP is turned off and monsters may not spawn or hurt players there.
Server admins can also create war zones, somewhat similar to safe zones. These zones however are not safe from PVP and monsters. Further, they can be configured to have friendly fire enabled (PVP between allies and faction members) and can be configured to have power loss disabled in them.
Individual Ownership of Territory
For territory that has been claimed by a faction, the faction admin (and possibly faction moderators) can further specify ownership of any claimed territory to anyone within the faction using the /f owner *[player name] command. This ownership will limit access to the territory to only those in the owner list, along with the faction admin and faction moderators. In general, these owned areas will extend the same protections which faction territory provides against those not in the faction to also protect against normal members of your own faction.
This can be used to provide private ownership of particular areas, or to provide a storage area for the faction admin and moderators which is safe against in-faction griefers.