so basically itd work like this
guild leaders can buy forts for their guild(s), where guild members can hang out and store loot inside a locked vault in the fort
this vault is the key part, as outside forces can also raid the forts (if they're present on the map) for the chance to take out the fort's defenses, kill the members, and take the loot for themselves
the forts themselves should be nameable and customizable, and have different variations depending on size and overall functionality
it'd also be interesting to have a sort of ship yard for all of the guild's ships, and the ability to customize what defenses youll have (skeletons, phantoms, ghost ships, etc etc)
idk, just a thought i had not too long ago
