The Shadow Sirens are three witches in Paper Mario: The Thousand-Year Door. They consist of Beldam, Marilyn and Vivian (later Doopliss). They aid Sir Grodus and the Secret Society of X-Nauts in their quest for Crystal Stars and retrieve the Magical Map from Mario and his friends. After Vivian joined Mario's team, Doopliss took her place.
Beldam, the leader of the Shadow Sirens, is often forgetful, and on more than one occasion, her forgetfulness gets Vivian in trouble. She is more of a magic user than the other two are. Marilyn is the biggest and strongest Shadow Siren in the bunch. Other than one line, "The Three", she is unable to say more than "Guh", and various forms of it. She can become stronger and hit hard. The Shadow Sirens are fought twice in the game. Beldam was the merchant from the intro of the game, as when Sir Grodus is talking to the 3, he asks Beldam why she didn't kidnap Princess Peach when she had the chance. Also near the end, Beldam says to the Shadow Queen "I spread rumors of the treasure and found a pure-hearted maiden."