The Sea King, also called the Mer-King, rules an underwater kingdom in the ocean's deepest unreachable depths from his coral palace. This structure features amber windows and a roof of water-responsive shells, each cradling a pearl. A widower since his queen's passing, he resides with his mother and six mermaid daughters. He delegates their upbringing and education to his mother, the dowager queen. Governing merfolk society through established customs, the Sea King enforces traditions including the rite allowing mermaids to visit the ocean surface upon turning fifteen. His daughters ascend annually to observe the human world under this rule. He neither curbs his youngest daughter's fascination with the surface nor prevents her visit to the Sea Witch, exercising authority through precedent rather than decree. Unaware of his youngest daughter's bargain with the Sea Witch, the Sea King remains uninvolved after her transformation into a human and permanent departure from the sea. His character remains static throughout the narrative, unchanged by events.