Sith Lord did not choose the color of his lightsaber. Always is red.the kyber crystals

There is a reason for the dark side of the Force use red sabers. Movies have never explained why the color of the lightsabers of Darth Vader, Darth Maul or Kylo Ren. But Ahsoka Tano's novel, starring Padawan Anakin Skywalker in Clone Wars, has revealed the mystery.

To explain, we must know what are made lightsabers: the kyber crystals, gems users who choose Force and shown them at will. But the dark side does not experience the same connection with these crystals from the icy planet Ilum. The only way to have the sith to seize these precious gems is killing the carrier lightsaber or stealing them. The act of bending the glass kyber at will makes the blood crystal, metaphorically, and take the red.

That is why, in reality, the Sith Lord did not choose the color of his lightsaber, but using gems against their nature, do they change their characteristic green or blue (and even purple) a bleeding tone. The Sith can never carry a green or blue laser sword, because by committing indecent acts the kyber crystals act against their will.

These gems are seeking Jedha Empire, the new planet that will appear in the next film in the series, Rogue One: A History of Star Wars. There would crystals kyber the Empire needs to build the Death Star, the stones used to build lightsabers and are vital for the Jedi.