Milly (Milayou in Dragon Warrior Monsters) is one of the main characters in Dragon Quest VI, being part of the party that accompanied the Hero in his quest to stop Murdaw and later Mortamor; she also appears in other titles, like Dragon Quest Monsters.

Milly is first seen with the Hero and Carver as they attempt to take on Murdaw at the beginning of the game. The three fail and Murdaw separates their bodies and souls by turning their physical bodies to stone while sending their souls to the "Dream World". The Hero and Carver will eventually find Milly again in Port Haven and it seems she's the only one who can see them. Milly takes the two to her Master, Madame Luca Luminista, who tells them how they can become visible. She sends the Hero, Carver, and Milly to the Lucid Grotto to obtain some Dream Dew that, when enchanted with a spell by Madame Luca, makes the Hero and Carver visible to others in the Real World (the dew is later used on Ashlynn, as well). Milly then leaves Madame Luca and becomes the party's third playable character.

As the story of VI unfolds, the player learns that Milly and Terry both lived as orphans in Felonia when they were children. Milly was sold by her foster parents into slavery to the local crime syndicate and thereafter to the King of Felonia as a dancer due to her remarkable beauty. NPC dialogue indicates she was also locked up in the castle dungeon for a time by the previous Queen of Felonia out of bitter jealousy simply for being 'too beautiful'. Milly later escaped, and met up with the hero before the first attack on Murdaw.

Upon Dhuran's defeat and the revealing of the true antagonist, Terry and Milly reunite. This grants her a new title and the team a powerful ally. After slaying Archfiend Mortamor, the heroes go back to their homes and Milly decides to apprentice under Madame Luca and become a Dream Seer.

After the game's credits, she calls everyone back to Madame Luca's house and uses her crystal ball to show them Zenithia, where the magical egg that will give birth to a bright new future is about to hatch and all look in awe as a new dawn is born.