A new zone in the open world that works similar to PvP zones where the guilds fight over control of some point of interest.
In said zone, all guildies (regardless of faction) would be friendly to each other, and everyone else hostile. There could be 3 points that all has to be simultaneously controlled. This is a neverending battle for supremacy.
There are two reward structures:
(1) At midnight between Sunday/Monday server time, whichever guild controls all points of interest become the Emperor/Conquerer/Ruler Guild. Emperor/Conquerer/Ruler lasts until there's another guild that control all the points at midnight between Sunday/Monday. REWARD: 1% of all vendor sales are funneled directly into their guild bank. And the guild master gets the title "Emperor/Conquerer/Ruler".
(2) Whichever guild has most accumulated time controlling all three points simultaneously over the last week wins. Reward distribution and reset at midnight between Sunday/Monday server time. REWARD: 10000 donation points divided evenly between all guild members that has been online in the past week. Meaning bigger guild, the more diluted reward.
There must also be a spotlight of current Emperor/Conquerer/Ruler guild and guild master on website, as well as leaderboard with guild with (1) all-time most Emperor/Conquerer/Ruler weeks, (2) all-time most accumulated time with all points controlled, and (3) guilds with current weeks accumulated time.