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Water elementals belong to the Conflux, but you could create sea elementals, for example, which differ slightly in appearance from their counterparts and, in terms of alignment, belong to the Haven. In general, Haven is more related to the surface, so why focus so much on the inhabitants of the seabed? There are also pirates, fishermen, and mermaids. Perhaps some huge albatrosses, the size of a Roc :) You could bring the sea beast from the fourth game, with its ability to absorb victims. An octopus is also a good idea, why not? An attack in three directions, no retaliation, and holding with tentacles like a dendroid with roots :) Neptunes with tridents. Water lizards. Monsters with a human body and a shark head (remember the first Blood). 50 percent water resistance for all Haven creatures (except for beneficial spells). Of course, Haven is located near the shore and can also be a shipyard, or even an altar for summoning a ship (if you don't have an expert in water magic or the spell itself). A 50 percent discount on building a ship if you are from Haven. The fishermen's guild brings an additional profit of 1000 gold per day. Bonuses in water battles (morale, luck, speed, attack, and defense). The ability to learn water magic for 2000 gold in the sea witch's hut. The mages' guild is full of water spells. The Grail is a huge, iridescent, living shell with a pearl inside, which, in addition to other bonuses, gives +200 percent movement speed on water for allied heroes. A lighthouse. Buoys near the shore that increase the hero's morale during a siege. By the way, you might have to develop two versions of Haven - one for the shore and the other for the open sea (although that wouldn't really be Haven anymore). Well, are there enough ideas for now? ;)