Thanks to Cloud BR with this awesome Alliance War system that we are running here on UO: Depths. There are 2 Alliances which a Guild can choose to be part of: Order & Chaos.

When making a guild you'll automatically join one of these 2 Alliances, so if you prefer another one your guildmaster must go to the guildmaster menu and change the alignment (note: you can only change alignment once every 7 days).

Once you enter an Alliance you'll automatically be at war with the other Alliance, meaning you can kill members of such ally anytime and anywhere, except for safe regions such as Luna and Umbra.





Everytime you kill an opposing alliance player you reward your guild with Alliance Points (the number of points you get is related to the skill sum of the opponent). Note that the more people fighting the more points you can get, because for every eligible attacker on the loot right list, your guild gets the points.
Note:Every 24 hours all guilds will suffer a 8% Alliance Points decrease.

But what to do with the points?
Alliance Points are used to start town dominations by your guildmaster.



If a town is currently under attack it's name will appear green on the menu and a red pedestal will appear in the town (if the town has already been taken the name will appear red).  But much more visible then the pedestal there'll be a Crimson or a Platinum Dragon.
Crimson Dragon will appear if the guild invading is from the Chaos Alliance and the Platinum one will appear if the guild if from the Order.



For your guild to successfuly dominate a town the dragon must be killed getting more damage from your Ally then the opposite.
Example:
You start a town domination and you are a Chaos guild, Order guilds and Chaos guilds go there. There are 10 Order and 10 Chaos.
The Order players give 100 damage combined while the Chaos give 101 damage. Then the invasion is succesfull, but if the Order players gave more damage, the invasion would be a failure!
Note: Pet damage also counts towards this.
Note2: If the invasion fails, the starting guild will receive back half of the points it spent to start the domination.



After killing the Dragon the town will be left unprotected if the guild that started the domination was a Chaos guild, and protected if it was an Order guild. This will last for 5 days after the invasion and anyone entering the town will see a message telling who is currently dominating the town.

But that's not everything:
After killing the dragon it'll start raining gold (much like a Champion) and it's loot is very worth the effort, with tons of magical items, artifacts, set pieces and peerless reagents.

Also, if the invasion is successful, every member of the guild that started and gave damage to the dragon will receive a special reward acquirable only through this system.
Examples: Sorcerer's Armor Set, bonded Charger of the Fallen, unique decorations.