
The Sea-Elves were habitants of one of the cities lost in the sundering beneath the sea. Tor Fenalorn , a city in the realm of Nagarythe, was a prosperous and wonderful city on the west coast of the elven homeland. Its architecture was considered some of the most splendid in Ulthuan. Its Nobles were as wealthy as those in the larger realms and their people as skilled and successful. Because of the mountainous nature of the region, the city was quite isolated. The elves of Tor Fenalorn were content to keep themselves to themselves. Trade was easier by sea, and its close proximity to the coast allowed this to flourish. They had their own army, their own commanders, mages and soldiers. Of course those days were long before the citizen levy system was introduced, so the regular people of the city were free to go about their normal lives just as every other Elf in those times.
The Sundering, a tragic event caused by Malekith the Witch King's evil plan to undo the magical vortex maintaining the balance of the island, caused the great city of Tor Fenalorn to be engulfed by thousand foot high waves. Earthquakes hit the entire isle, but the realm of Nagarythe was hit the worst. Tor Fenalorn was in grave danger.
Just in time their Archmage, Anwane Forhaldis, cast a protective spell over them and, although they couldn't save their city from sinking, they survived underwater in a sphere of magic. This sphere protected the city from total devastation from earthquakes, but meant the land was separated from the island of Ulthuan. The city and its surrounding lands drifted away to the west, and settled at the bottom of The Great Ocean. Many other cities and settlements were not so fortunate, and thousands and thousands of elves lost their lives in this epic disaster.
Tor Fenalorn, while not utterly destroyed, still took great damage. Wall and towers collapsed under the strain of the land itself moving, the city became very unstable. Now, at the bottom of the sea, the place was in total darkness. Forhaldis, his council of mages and the Prince of Tor Fenalorn, worked together to use magical energy to give the city light again. Somehow they were successful, and artificial sunlight beamed down over the ruined realm.
Gradually the city was rebuilt, and the Elves learnt new ways of striving using the resources they had. They began to venture into the deep sea outside the magical sphere, not just for resources but to explore, and the people of Tor Fenalorn continued their way of life in a new environment.
Over the years they befriended many creatures of the sea - much like the elves on land befriended the Eagles and Dragons. The elves natural ability to communicate with other creatures has seen them have many allies, in the shape of Great Rays, Turtles and Crustaceans.
Living at the depths of the ocean has caused the elves to differ in appearance, their skin now a grey/blue, and they have gained the ability to breathe underwater, for when they need to venture from the magic sphere enclosing their city.
Their mages have used enchantments to grant them tails of great fish, allowing swimming to be far easier and faster, and it is the mages who venture from the city the most - to gain more underwater allies.
There has been no clue to any inhabitant of the world above water that these Elves exist - until now. The tides of chaos are forcing the Sea Elves to go to war for the first time since the sundering. Not that they aren't prepared. They still trained in all aspects of battle vigorously, knowing this day would one day come.
When fighting on land, the Mer-Mages call the water forth from the ocean itself, allowing their many allies to join the battle. While the mages haven’t the power to summon enough water to flood the battlefield to drown the enemy, they can certainly call enough for the sea creatures to swim. Their warriors use huge tridents - weapons of their sea lord, and their archers have lost none of their skill from ages past. The Sea-Elves ride atop mighty Mer-Dragons and magnificent Great Rays, and their knights have trained to ride upon not elven steeds, but giant sea horses the mages made connections with.
The Phoenix King shocked at first that some Elves thought lost, had survived, welcomed the new allies. He now includes them as a willing army to take the fight back to the evil races of the world.