Guinevere, also known as Princess Prin-Prin, or simply the Princess, is the helpless damsel whom Arthur saves time and time again in each successive installment in the Ghosts 'n Goblins series. She has an extremely powerful ring in her possession which is able to destroy the Demon Emperor Sardius. She also has a magical bracelet.
In Ultimate Ghosts 'n Goblins, she is the last human on earth with royal blood in her veins, and the reason for her repeated kidnappings is made much clearer. Apparently, she is to be impregnated by a demon, thereby giving the Ghoul Realm control over the monarchy.
- In Ghouls 'n Ghosts and Super Ghouls 'n Ghosts, during the cast roll, B.83 W.50 H.89 appears under her name. These are the measurements of her bust, waist, and hips in centimeters.
- The plot dynamic between Arthur and Guinevere is similar to Nintendo characters Mario and Peach, with Mario constantly having to save Peach from being kidnapped, usually by Bowser.