Originally a sorceress allied with Anselm, Hedwig's lust for power led to conflict and her banishment beneath the ocean. This exile forged her into the primary antagonist dwelling in a deep-sea lair.

She possesses a mermaid-like form with a moray eel tail. Her abilities include conjuring prehensile vines from elongated fingernails to ensnare foes, crafting potent magical potions, and wielding enchanted objects like a hypnotic flute for control. Hedwig relentlessly seeks the Amulet of Power, believing it grants dominion over land and sea. To secure it, she repeatedly attempts to capture Marina and Prince Justin for leverage.

Her operations depend on aquatic minions. Dudley, a dim-witted but loyal hammerhead shark, serves as her principal henchman and endures constant abuse, providing comic relief. Other subordinates include Ray (or Manta), a manta ray used for transport and spying; Hugo, a giant Pacific octopus supplying brute strength; and armies of barracudas and bull sharks. Their frequent failures due to incompetence ignite her volcanic temper.

Her schemes extend beyond the amulet quest. She once transformed Marina’s sister Coral into an infant via a youth potion, though Coral’s resulting chaos forced her to reverse it. In another plot, she nearly subjected Marina to a traumatic haircut. Her magic sometimes rebounds; a "Potion of Reverse" temporarily rendered her benevolent, a state even her minions preferred, hinting at a latent capacity for goodness suppressed by ambition.

Human alliances fuel her antagonism. She partners with adversaries like Prince Lothar of Brakston and Cecily, Justin’s jealous aristocratic fiancée, aiming to thwart Marina and Justin’s relationship, though these typically fracture from mutual distrust.

Across official media, she remains consistently power-hungry and vengeful. One narrative conclusion depicts her transformed into a non-threatening sea dragon, adapting to a new existence, ending her menace without erasing her core nature.