Can only be done in the Grand Line
The first crew to discover and successfully complete a mission on an island receives 100 influence points towards that island, granting them T1 Influence.
The Captain or a T2 and beyond First Mate can do the Influence DTA
For 2 DT, the Captain or higher tier First Mate of a crew on the island can make a Persuasion or Intimidation check and increase or decrease the island's influence by the result. A crew may only positively influence an island if no other crew has no influence score on that island. If another crew has influence on the island, the opposing crew can only de-influence the island.
Influence is a tiered system
T1: 100 Influence: The crew gets to make a filler mission that anyone can complete on that island. Contact an Admin for instructions
T2: 200 Influence: The crew receives 500k berry per week from that island. It may be split up however the crew decides
T3: 400 Influence: The captain receives a custom benefit. Contact an Admin for instructions
There is a maximum of 500 Influence on an island, though, increasing beyond 400 has no tier benefits.
When a crew successfully decreases another crew's influence score on an island to 0, the captains meet to discuss possible PvP for influence priority.