A new player activated world event occurs with a unique cloud and a mark on the map. This will be at one of the forts including FOD. How the fort operates, the theme, lore, rewards etc have to be cool/worth it but are a distance second to how players can start it.

It starts via an song of siren skull reskin placed on either the shull at the FOD or at the armory at a standard fort. You get the skull at random by doing old content, different contient each week, there is extra rep and rewards plus at random a dig up quest on the fort in question. E.g.

Lost shipment week: the dig up will be in a bottle in the captains quarters.
Merchent drop commodities: every x gold at grade five will award the voyage, claimed you do a merch grade 5 voyage.
Ashen winds week: the lord will drop a bottle along with their skull.
FoD, Gold horder vaults: its in the vault
Etc.

Result, old content back in the mix, Reapers can target players doing this old content for completing the rewards.