Cubus Sisters

The Cubus Sisters are a group of four demonic sisters living on the Ghost Ship that serves as the boss of the dungeon in The Legend of Zelda: Phantom Hourglass. They originally trick Link into believing that they are four young Hylian girls that were trapped on the Ghost Ship like Tetra was and spend the majority of the dungeon trying to indirectly harming Link by giving him wrong answers to some puzzles or feigning to be afraid to alert the Reaplings.

Battle
Three will shoot laser down at Link while the fourth will send down an energy ball. In a game of Dead Man's Volley, Link must hit the energy ball back to the sister with his sword. Once a sister is gone, the remaining three will start hitting the energy ball between themselves to disorient Link. Once only one remains, the sister will generate two false ball of energies to go along with the real one. These false ball will hurt Link on contact. Once defeated, Link will obtain a Heart Container and the Ghost Key, which opens the secret room of the Ghost Ship where Tetra is held captive.

Trivia

 * The Cubus Sisters are the first ones to use the term "Dead Man's Volley" to reffer to the classical battle technic used across the series.