system
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human
[Star Wars] In many SW games the color of a lightsaber says something about its wielder. How was this envisioned for the original trilogy (green, blue)? How did this change (yellow, purple) with the games and/or new trilogy? Which parts are considered canon in the expanded universe?

Okay, lots of questions. Basically I'm asking because there seems to be little to no significance in the difference between blue and green sabers in the original trilogy but it becomes an important factor in games like the *Knights of the Old Republic* series (yellow) and *Jedi Knight* series (purple, orange, ...). And let's not forget Windu's purple saber in the new trilogy...

So, what is considered canon in the expanded universe? Does color not signify anything specific (red being obvious) or is there a reason for every Jedi to have its own color as in the excellent KotOR series?
gpt
The Expanded Universe is Canon, but not to the movies. It's considered Legend, meaning it's its own sort of miniverse.

Think of it like the Star Trek franchise. The New Movies are made free of any information given, or lore created in the series or other films, because  of the alternate timelines.

As for Lightsabers. Luke originally wielded a blue blade like Obi-Wan, because it was Anakin's lightsaber, Obi-Wan and Anakin were both Jedi Guardians. He later got a green one because unlike his father and mentor, he was a Jedi Consular, like Qui-Gon Jinn.

In KotOR, when you first become a Jedi, your blade colour shows what class you are, it's cool, but changeable (the blade, not the class). 

Blue is for Jedi Guardians, like Anakin, Obi-Wan, etc. These Jedi specialize in combat, and are often generals and military advisers.

Green is for the Jedi Consulars, like Luke, Qui-Gon, etc. These Jedi specialize in diplomacy and force mastery, they are often diplomats.

Yellow is for the Jedi Sentinel, like Bastile Shan and Visas Marr. These Jedi specialize in a variety of skills, often acting as scouts, messengers and spies.

Red signified the Sith, who only had access to synthetic crystals, and then wore that colour with honour.

This distinction fell out of practice in later years when most Jedi used blue or green crystals from Ilum Caves based on personal choice, and then the use of crystals coming from various source worlds became marginal. No longer having Ilum crystals at their disposal, Jedi of the New Jedi Order favoured the use of various crystals and gems, creating lightsaber blades of multiple colours.

In Jedi Knight, the reason that you can have any colour, is because Jaden Korr built his lightsaber before entering the Jedi Academy, meaning that he didn't know what type of Jedi he was, and most likely went for what looked cool, or whatever he could find.

Mace Windu's lightsaber was rare. It was purple because of the Hurikane Crystal he used for it, after demonstrating immense Force Mastery to the Native People of Hurikane, who gifted it to him.