Ever since the Hunter's Call was added, it's seemed like a great idea, but I feel like it's had relatively poor execution compared to the other trading companies. I think that giving it an emissary flag and some proper quests could reinvigorate the hunters and make people more willing to use them as their primary faction. I've roughly based my voyage ideas on existing precedents in other trading companies so that they don't end up being extreme or overpowered, but at the same time I've tried to make them unique in some ways.

Emissary Flag

The Hunter's Call flag would work in mostly the same way as the others, with it gaining value when you pick up treasure such as mermaid gems and place them on your ship, but it would also gain value when you first catch a fish, and again when you finish cooking it to match the way you get it twice from other treasure. It would also gain value when you kill a megalodon (like the others do), but the value could possibly be increased for hunters because megalodons are what they "hunt", or maybe it would scale with the rarity of the megalodon. Unlike the other flags, the hunter flag would also increase in value when you killed a kraken tentacle, and maybe also when you killed the entire kraken. You would only be able to buy the flag from an official Hunter's Call representative at a seapost, but there would be a table at outposts where you could raise it, like the table where you raise the reaper flag.

Quests

Like the other trading companies, the hunters would have two main types of voyages. The first would be a fishing voyage, and the second would be a hunting voyage.

Fishing Voyage

This voyage would be similar to the merchants' commissions, but instead of animals it would be fish. The voyage would request specific types of fish, and you would have to catch them and return them either to any Hunter's Call representative, or possibly to a specific one. The fish that are requested would depend on the area you were in at the time you started the voyage (for example it could ask for Ancientscales if you were in the Ancient Isles), but they could also ask for common fish like Splashtails. Once you went out and caught the fish, you would be able to sell them for a higher price, similar to how the merchants pay extra for commissioned goods.

Hunting Voyage

This type of voyage would be somewhat similar to the Order Of Souls' ghost ship voyages. When you start the voyage, it would give you a location, either near a specific island or in a set of coordinates, and you would go there to fight something. Most of the time this would be megalodons, but it could also sometimes be krakens [Edit: and maybe other sea monsters if they were added]. They would just pop out of the water like they normally do, but instead of being random or based on a world event, they would appear when you arrived at the specified location. They would scale based on your ship type like they normally do, but the megalodons wouldn't necessarily have the same movement and attacking patterns. One thing that would be different would be that they wouldn't just disappear forever like they normally do. If you were on a quest for a megalodon and you got too close to an island or went too far away, it would still go under the water and disappear, but when you went back to the location listed in the voyage, it would come back. It could come back at its existing health, full health, or healed by some amount based on its rarity, depending on how it was implemented. Once you killed it, it would drop somewhat random loot, but it would not use the regular loot tables. They would drop loot that could be sold to the hunters, like fish in barrels, mermaid gems, and maybe even new treasure if the developers felt like adding new items, in addition to the meat. These would increase in quantity and quality depending on how good the voyage was (which would depend on how many Hunter's Call promotions the player had), for example if the voyage was better the barrels could have more fish and a higher percentage of the fish being trophy, there would be more mermaid gems and they could be more likely to be the more valuable varieties, and there would be more meat. This loot would also have birds circling it like natural barrels do, so that they players wouldn't go on a whole quest, only to be unable to find the loot. I would love it if this mechanic could also be applied to loot dropped from regular sea monsters and skeleton ships, but that's probably a topic for another post. The way this type of voyage would affect the emissary flag is similar to the written Gold Hoarder voyages, where your flag increases in value when you arrive at the destination, again when you pick up the loot, and a third time when you put it on your ship.

Possible Third Voyage

I came up with another type of voyage that's somewhat similar to the other two, but that is probably worse and not worth adding. It would be where you get a location and a list of fish to catch, and those fish are more common in that area. They would then sell for an increased price because they had been requested. This one seems more boring/easy than the others, but I felt like I should mention it anyway.

Hunter Perks

If this was implemented, the hunters could also possibly sell you increasingly better tools (fishing rods and something else), a costume, and eventually a whole ship set. I know they already have this in a way with the killer whale stuff, but I feel like they should get some proper "Hunter's Call" gear. Maybe the killer whale stuff could become exclusive, go on the black market, or be incorporated in some other way.
These changes could go a long way towards making the Hunter's Call feel more like a legitimate trading company, and less like an excuse for them to add fish.