From the article
" New leaks reveal dramatic scenes featuring Kylo Ren on Mustafar and start to explain why the Knights of Ren have been so conspicuously missing from all Last Jedi merchanising, imagery and footage... Until now."
"Mike Zeroh cites sources at Pinewood and other Star Wars sets around the world.
He says: “A report a few months ago said the sequel trilogy would be returning three planets we have seen in the Star wars movies – Endor, Mustafa and Tattooine.
“We have heard that Mustafa will be used in The Last Jedi for a small segment."
"If it is just a short scene, it only makes sense this is a flashback. In Rogue One they introduced Darth Vader’s Castle on Mustafa. This was also done for future films. There is a great chance Kylo will be leading the Knights of Ren to Darth Vader’s castle to recover artefacts."
Kylo's obsession with his grandfather was set up in The Force Awakens when he was shown gazing at Vader’s burned helmet and talking to it like an entirely sane little psychopath. Other reports have speculated that Kylo Ren will be seeking a fragment of Vader’s shattered lightsaber to help complete his own imperfect blade."
"The sequel trilogy seems to be incorporating many more aspects of Star wars lore, with references to the Book of Whills at the Jedi temple. StarWarsTheory also revealed that Luke Skywalker has an ancient compass that seems to use the Force for some mystical purpose.
The latest leaks also finally shed some light on the total absense of the Knights of Ren so far in the build up to Episode 8.
Fans have sensed a disturbance in the Force. What is being hidden?"
Edited by Imperial Advisor Arem Heshvaun