A full body shot from a low angle depicts the menacing boss of the deep-sea city, a demon king and hidden child of Neptune, floating centrally in a fantastical underwater abyss. The character has long blue hair, demon horns, fin-like ears, and shimmering fish scales across her skin; her crystal-like eyes are awakened and glowing, casting a condescending gaze downward. She wears a skimpy, tattered dancer's outfit that exposes her midriff, accented by golden earrings and a golden necklace. Her hands are open and gesturing as she manipulates the surrounding currents, while two colossal, blood-stained legendary tridents of Neptune—too massive to be held—float ominously in front of her, pointed forward. The background is a surreal, haunting seascape of ruins and deep-sea flora, enveloped in a sinister, overwhelming aura. The visual style is a high-quality anime illustration with high contrast, featuring a dark palette of deep oceanic blues and blacks pierced by the brilliant, iridescent glow of her scales and the menacing energy radiating from the oversized weapons.