Yes, some Sith have used blue lightsabers, especially in the Star Wars Legends (Expanded Universe), with notable examples being Exar Kun and Darth Revan (who also used purple), and even Darth Sidious in one instance; however, red is the iconic Sith color due to bleeding synthetic crystals, though some Sith, like early Darth Vader, used their original blue Jedi saber for a time before switching.
While Sith usually corrupt their crystals to produce a red blade, there is no hard rule that prevents them from using a different colour, including blue. This could occur if a Sith acquired a blue lightsaber through theft or other means, or if a former Jedi turned to the dark side without changing their weapon.
After destroying the Jedi Temple in 28 ABY, Ren used the dark side of the Force to bleed his lightsaber's kyber crystal, changing the color of its plasma blade from blue to red.
Both Exar Kun and Ulic Qel-Droma were Sith and used non-red lightsabers (blue and green if I remember correctly), as depicted in the Legends Tales of the Jedi comics.
Tràkata is a rare and cunning lightsaber technique built on deception and misdirection. Jedi like Kao Cen Darach and Cal Kestis used it to gain surprise advantages in battle, while Sith like Qimir mastered its lethal precision.
Vader breaks free of the operating table and takes a few steps before doing the only thing anybody in his position could do, he screams an unholy, bloodcurdling scream. His vocal computer has nothing close to this sound in its database so it translates it to the infamous 'Noooooooooo'.
Born on the planet Hyperkarn in 15 ABY, Rey was the daughter of Dathan and Miramir. While their names were lost to history, Rey's father was the cloned son—an artificial genetic strandcast—of the resurrected Darth Sidious, making her the granddaughter of the fallen Galactic Emperor and Dark Lord of the Sith.
Qui-Gon Jinn's simple yet elegant lightsaber served him in many conflicts. The maverick Jedi designed his green-bladed saber to imitate the weapon of his master, Count Dooku; Qui-Gon's saber, in turn, inspired the design of Obi-Wan Kenobi's first Jedi weapon.
The Many Forms Of The Saber
The Ghostfire Kyber Crystal is one of the rarest in the galaxy, known for crafting silent, nearly invisible lightsabers with ghostly afterimages. Found in remote Outer Rim peaks, it features in Star Wars Legends as a weapon of stealth and illusion.
"The Stranger," as he was known, was a former Jedi who became a Sith Lord in the later years of the High Republic era. Claiming to have no name and going by the alias "Qimir" in his public life, the enigmatic male individual who became known as "the Stranger" was a human alive during the High Republic Era.
The Code forbade the Jedi from killing unarmed opponents as well as seeking revenge. Amongst other dictates, the Jedi Code forbade Jedi Knights and Jedi Masters from training more than one Padawan at a given time. Attachment was also forbidden by the Code.
Likely unaware of his true nature, Snoke was an artificial genetic strandcast created on the planet Exegol by the resurgent Dark Lord of the Sith and Galactic Emperor Darth Sidious as a proxy and the product of cloning experiments.
No, Darth Plagueis is not Anakin Skywalker's biological father, but there's a strong theory (especially in Star Wars Legends and early drafts) that his experiments with midi-chlorians to create life led the Force itself to create Anakin, the Chosen One, as a reaction, making Plagueis the "unintentional father" of the prophecy. In current canon, Plagueis is a legend Palpatine uses to lure Anakin, and the exact nature of Anakin's conception by the Force remains a mystery, though he had no conventional father.
Luke was the last Jedi, then. Rey is the last Jedi, now. The title of each film in the sequel trilogy is a direct reference to the main protagonist of the sequel trilogy, Rey. In the Force awakens, it awakens in her.
So: which lightsaber is the most powerful? The answer depends on what you value most: the devastating raw power of Kylo Ren's unstable blade, the symbolic might of Anakin Skywalker's blue saber, the balance reflected in Rey's yellow lightsaber, or the legendary authority behind the Darksaber.
Darth Maul is the weakest. Bane was strong : he killed all the Sith and lots of Jedi.
The saddest Star Wars deaths often involve poignant sacrifice, broken relationships, or innocent lives lost, with fan favorites including Kanan Jarrus (heroic sacrifice for his family), Duchess Satine (Obi-Wan's lost love, brutally killed by Maul), Clone Trooper 99 (innocent loyalty and tragic end), Tech (sacrifice for his squad), Padmé Amidala (heartbreak and loss of hope), and Han Solo (fatherly tragedy). These deaths resonate due to their emotional impact, the characters' potential, or the deep impact on other heroes.
Immense anger and hatred. No sadness, no confusion, he as Vader knew exactly who she was and it no doubt enraged him beyond belief to be referred to as if he were still Anakin.
Therefore, from a categorical perspective, our psychiatric diagnosis of Anakin Skywalker is BPD.