Grace O'Malley captains the pirate ship Rumble Rose, leading its all-female crew. She possesses dark skin, red hair worn in a low ponytail reaching her hips, brown eyes, and a distinctive eyepatch covering her right eye. Her personality is strong and arrogant, marked by a pronounced aversion to losing.

Royal Navy officer Abel Bluefield hires O'Malley to capture Fena Houtman. During this mission, O'Malley engages in a sexual relationship with Abel but grows jealous due to his obsessive fixation on both Fena and Fena's deceased mother, Helena. After ambushing Fena's group in Orléans, O'Malley successfully kidnaps Fena and delivers her to Abel aboard his ship, the Blue Giant. Abel refuses payment, citing the requirement to deliver Fena unharmed due to a minor injury sustained during capture.

Retaliating for the denied payment and fueled by resentment over Abel's dismissal, O'Malley orders the Rumble Rose to attack the Blue Giant. The Royal Navy ship retaliates with its Wellington Cannon, a powerful naval artillery weapon. The bombardment completely destroys the Rumble Rose, killing O'Malley.