Before it was renamed the Ceosal Kingdom, this underwater fortress was known as Aquitas. Aquitas was created by the Goddess of Light, Meihui, and the God of Rain, Yuzan, in 1 BC.
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Aquitas' first rulers were King Eärendil and Queen Aerwyna. Their days of birth are unknown, but some believe that they were the first of their people to swim the seas of Naestrirea. They were loved and respected by all because they could see their King and Queen treasured all equally.
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That very prosperity was threatened when King Eärendil engaged Khaisitha in what was to be called the Mer-Avian Battles in 788 AC. For several years, the avians of Khaisitha stole food from their territory. At the time, there were unstable weather conditions and a plague that only infected the Mer. The unstable weather conditions affected each country differently. In Khaisitha, they experienced a drought, which forced avians to feed from other territories regardless of boundary lines. King Eärendil was also desperate to keep his people well nourished in the time of plague.
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The Siren Virus (known by outsiders) or Poseidon's Affliction (known by locals) caused Mer to fall into madness. Their skin would be necrotizing and oozing with pus, their eyes bloodshot and yellow with jaundice, and their scales turned white. Many Mer that suffered from this Affliction often forgot who they were, so many tried to cut their tails off, thinking it a simple costume. This Affliction took 346,276 lives from Aquitas.
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After a few months when the drought ended, but the plague persisted, an armistice was drawn. Mer that survived remained bitter from the whole ordeal, which is why they minimize contact with the avians and the surface world for centuries to come.
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In 989 AC, King Eärendil passed away due to old age, leaving his only child, Raina, to ascend the throne as Aquitas' new ruler. Queen Raina wed a noble warrior from the King's Guard, Leith, who subsequently became King. They had three sons: Aenon, Leomaris, and Merrick. Poseidon's Affliction was still rampaging through the waters, taking several hundred lives every month. Unlike her father, Queen Raina sought a cure. She was unsuccessful in her mission and passed away from the Affliction in 1123 (see A Queen's Will in Ceosal Kingdom Tales, Book 3.5).
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In 1123 AC, Queen Raina's eldest son, Aenon, ascended to the throne with Thalassa as his Queen. Both passed away in 1136 AC during the Poaching. They had no children that could ascend the throne, so late Queen Raina's second eldest son, Leomaris, took the throne with Marea as his queen.
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From around 1136 AC to 1336 AC, mermaids were poached by humans (the "Poaching"). Humans would cast their nets into the water and capture merfolk, only to use them as trophies and representations of their latest conquest. King Leomaris called the Deity of the Seas to assist them, but was met with silence. He petitioned the government of many nations until Khaisitha, an unlikely ally, agreed to help. Khaisitha thought that the act would help improve relations between the two nations and build mutual trust, and it did in the end.
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Humans were cast away as the lowest being on Naestrirea's food chain. The only country that would take in the remainder of their people was Wuzhen. However, after the run-in with the humans, the inhabitants of the Ceosal Kingdom decided to never walk on land again.
In 1474 AC, King Leomaris passed and his only child, Llyr, was installed as the new King. He married Arista and had four children in the following centuries: Lorelei, Nereus, Kairius, Marilla, and Ecthelion.
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At this point, the Affliction had claimed 75% of the Mer population. King Llyr petitioned the Vale of Aestreria for assistance. The fairies of the Vale assisted in eradicating the Affliction in the known population, however, banished or rogue Mer were excluded from the healing process since their exact location remains unknown. As of 1480 AC, there are no newly reported cases of the Affliction.
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Aquitas was renamed to the Ceosal Kingdom in 1479 AC.
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King Llyr seeks to forge an alliance with King Ren’s kingdom in the Raeyeong Ocean (see Broken Bonds, Book 2.5).