Cubus Sisters

The Diabolical Cubus Sisters are the fourth Boss in.

Strategy
Three will shoot laser beams down at Link, while the other will send down an energy ball. In a game of Dead Man's Volley, Link must hit the energy ball back at the Cubus Sister. Once the first is gone, the remaining three will hit the energy ball between themselves to disorient Link. Once only one remains, it will also send out two fake energy balls that will harm Link if he hits them. The fake ones look different from the real energy ball, so Link can distinguish them. Once defeated, Link will receive a Heart Container and a key to a secret room of the Ghost Ship.

Trivia

 * The Cubus Sisters' name references the Poe Sisters of, who share a Poe-like appearance, relativity, and four siblings with their precedents.
 * The name "Cubus" may branch off of the last five letters of the word, which refers to a female demon which seduces men in order to steal their life force.
 * In the Japanese version, the Cubus Sisters only made sounds when they fired energy balls, they were given a sound for receiving energy balls and dying in the international versions.