In the recent LEGO Star Wars Terrifying Tales holiday special, the story of how Ben Solo joined up with the Knights of Ren is told by Vaneé, the creepy attendant of Darth Vader’s Castle.
The special isn’t canon, however, so while it was really cool to see this story told, fans might be wondering: what’s the true story? What really happened? Well, we know the truth from a four-part comic miniseries that was released around the time of The Rise of Skywalker, written by Charles Soule, called The Rise of Kylo Ren. And this LEGO special does get a lot of the overall details right: Ben Solo grows frustrated with his training under Luke Skywalker and joins the Knights of Ren, who tell him he must pass a test of destruction before joining. And in the end, Ben winds up killing the leader of the Knights – a mysterious man named Ren – and takes his place. But the specific details of how this all happened are different than as told in the LEGO special.
Ben Solo first met the Knights of Ren years before he joined them, as he traveled with Jedi Master Luke Skywalker and explorer Lor San Tekka to an ancient Jedi outpost on Elphrona in search of history and artifacts. Upon arriving, however, they found Ren and the Knights of Ren already there, scavenging and plunging the Temple. Luke stepped up and engaged the Knights in combat, swiftly defeating them – and making it look pretty easy, as his admiring nephew and apprentice looked on. But before Ren retreated, he alluded to the “shadow” within young Solo and made him an offer to join them, whenever he felt ready.
Years after that came the fateful night where Ben clashed with Luke in his hut. It was seemingly only a misunderstanding at first, and even in the aftermath Ben didn’t intend to destroy the Temple. In shock and horror over what had happened, and feeling like he couldn’t return home to his mother, Ben fled for refuge to Snoke on the Amaxine space station. Ben thought about joining the Knights of Ren and Snoke urged him to do so, sending Ben on a hunt for them. He caught up with them, but not before three of his peers from the Jedi Temple tracked him down. In the ensuing fight, one of them – Hennix – was killed. Ben later recounted this to Ren, who was unconvinced about Ben’s true motives but accepted him into their ranks anyway, giving him a change of outfit.
But as Ren led the group, Ben didn’t want to see innocent people killed – leading to him opposing Ren. At the same time, the remaining two Jedi students showed up to finish the job against Ben. Ren killed one of them – Tai – right in front of Ben, and the young Solo engaged the leader of the Knights of Ren in a lightsaber duel, wielding both his own saber and the saber of his fallen comrade. With the fate of the galaxy in the balance – and with Palpatine and Leia both sensing what was happening – Ben drove a lightsaber through Ren’s heart, killing him. In the aftermath, Ben killed the remaining Jedi student – Voe – cementing his fall to the dark side. He assumed command of the Knights of Ren as their new leader, bled his lightsaber crystal red, and built the crossguard saber.
He would, of course, redeem himself years later on Exegol, when Ben Solo faced off with the Knights of Ren – who had apparently been summoned to Palpatine – and killed them all as he raced to help Rey.
So this backstory about how Ben Solo met the Knights of Ren and joined them is different than in the LEGO special, but obviously some of the overall plot points are the same. Disillusioned with Luke, Ben joined the Knights of Ren and killed Ren, taking his place as the leader of the Knights and officially embracing the darkness within.