Have you ever wondered why bad guys in Star Wars only use red lightsabers, and good guys get all the other colors? The secret has finally been revealed after almost 40 years!

We've seen a lot of different lightsaber colors. Green, blue, yellow, even Mace Windu (Samuel L. Jackson)'s purple lightsaber have been shown on screen. But what about Vader, the Emperor, Darth Maul, Count Dooku, and now Kylo Ren all having red lightsabers?

Since we were first introduced to the lightsaber in 1977, it's most definitely been a question on SOMEONE's mind. Of course, it's easier to visually pick out in a saber fight, but it's more than that. And the explanation is more than satisfactory, IMO.

The new Star Wars book, Ahsoka, which is considered canon, finally gave us the answer. Screen Rant put together a list of 15 Star Wars secrets from the book, including why the red lightsabers.

Star Wars has always made the affiliations of its Force users very clear: the dark side has red sabers and the light side has all the others. This is useful from a visual perspective, it helps the audience know who’s who, but is there a functional reason? Why doesn’t a Sith ever choose to use a blue or green lightsaber? Ahsoka provides a very clear answer to this question: because they can’t.

Kyber crystals choose Force users and present themselves to their desired owner, but dark siders don’t experience this same connection to the crystals. The only way the Sith and other dark side Force users can collect kyber crystals is by stealing them or plundering them off the bodies of their fallen foes. Even if a dark sider were to acquire a kyber crystal from a green or blue, the act of bending the crystal to their will in a new lightsaber will cause the crystal to “bleed,” turning it red.