As for why his blade looks different is because his crystal is cracked, resulting in a sparking blade, this is also because the crystal can barley contain the weapons power. Why does Kylo Ren's lightsaber have a hilt? Technically, all lightsabers have hilts. The hilt is the entirety of the handle of a weapon.
Like its wielder, Kylo Ren's blade is unstable due to the cracked Kyber crystal it was forged with, giving the blade a more menacing and chaotic look in contrast to other Sith lightsabers like Count Dooku's and Darth Vader's.
The lightsaber's redesign was a byproduct of the bleeding process that damaged its kyber crystal, rendering it dangerously flawed and unstable, and necessitating the lateral vents were meant to prevent the cracked kyber crystal from overloading.
We've known for years now that Kylo Ren's lightsaber crackles and sputters the way it does because the kyber crystal that powers its blade is unstable.
Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth. Instead, he was just a chaotic mess of the dark side (until he eventually found his way back to the light).
1 Darth Sidious
As well as being a gifted bladesman Sidious' connection to the Dark Side is extremely powerful, granting Sidious the ability to conduct force lightning.
As for why Luke uses his blue lightsaber instead of green in this projection, he knows it will impact Kylo Ren, who believes the Anakin Skywalker lightsaber should belong to him.
In The Last Jedi, during Rey and Kylo Ren's confrontation in Snoke's throne room, Luke's original lightsaber was split in half, and as shown later on in the movie, the crystal had been divided too, but in The Rise of Skywalker, which takes place one year after the previous movie, Rey is shown to have rebuilt it.
Gathering his strength, Kylo hurled his Sith lightsaber into the sea. Ben Solo had returned. Ben returned to Exegol, where Rey had confronted Palpatine. She gave him the Skywalker lightsaber, which he used to strike down the Knights of Ren.
What is the connection between Kylo Ren and Rey? As Kylo Ren himself says in The Rise of Skywalker, he and Rey are bonded not just by their familial legacies (Ren as the grandson of Darth Vader and Rey as the granddaughter of Emperor Palpatine) but by their unique connection in the Force.
The weakest and most harmless type of lightsaber is the one that has been “baby-proofed”: the training lightsabers. As the name implies, this type of lightsaber is only utilized in the context of training very young Jedi to one day become Jedi Masters.
As explained in the expanded lore, Kylo Ren cracked his kyber crystal while bleeding it–which is the process of creating a red lightsaber from its original color, and is something that can only be done through the Dark Side. This caused his lightsaber to spark and sputter whenever it was activated.
A crystal embodies the Jedi as the heart of the lightsaber, and pure kyber has no color until it's bonded to the Force user. This process likely resulted in Rey Skywalker's lightsaber being yellow.
Being the grandson of Darth Vader and nephew of Luke Skywalker, who we know to be powerful Force users, likely gave him a boost since the Force is strong in their family. Good or bad, Ren has received training Rey hasn't.
Though initially trained as a Jedi by his uncle Luke Skywalker, Ben was seduced to the dark side of the Force by Supreme Leader Snoke, and aspires to be as powerful as his grandfather, the Sith Lord Darth Vader / Anakin Skywalker.
We learned in The Force Awakens: The Visual Dictionary that the now-infamous red lightsaber had a cracked kyber crystal. Thanks to The Rise of Kylo Ren #4, we now know that the broken crystal is a result of the bleeding process.
He gave it to Luke Skywalker, who lost it when Darth Vader struck off his son's hand in Cloud City. The lightsaber then became part of Maz Kanata's collection of Jedi curios, where it called to the scavenger Rey.
Luke's green lightsaber in Return of the Jedi is a new lightsaber he built for himself. It is a completely different lightsaber from Anakin's lightsaber, which Luke loses during his duel with Vader in Empire Strikes Back.
The actual reason that Luke Skywalker ended up with a green-bladed lightsaber rather than the expected blue had nothing to do with storytelling and everything to do with real-life practicality. Luke Skywalker's lightsaber was changed from blue to green when they were filming because it was difficult to see.
The main reason for the change was that during the filming of Return of the Jedi, the crew realized that the blue saber did not look right during the battle with Jabba the Hutt. When shot in daylight, the blue would blend with the color of the sky, so George Lucas and his crew decided to make the change.
Obi-Wan Kenobi's third lightsaber was his new weapon that he created during the Clone Wars upon his promotion to Jedi Master and wielded until his death after his rematch with Darth Vader on the Death Star.
Master Yoda has risen above all others to claim the top spot as the most powerful Jedi of all time and the true chosen one according to IGN's audience. He won pretty handily as well, as he was victorious in 89,756 of his 95,243 battles and had a win percentage of 94.2%.
As the first Dark Lord of the Sith, Ajunta Pall founded the first Sith Empire and expanded it onto other worlds. The Sith took over the planet Ziost and created it as their capital and as Pall's new home.