Was that lava planet Mustafar or Sullust?
Pablo Hidalgo confirmed the former.
Interested to hear an explanation as to why Vader’s spending his days on the planet where he lost his arm, legs, lungs, hair, perfect skin, and wife.
The visual is certainly cool though. Plus maybe Rebels reference - “Mustafar is where Jedi go to die.”
(and I don’t think Sullust would make sense anyway - why would the Rebel fleet mass around Vader’s hangout world?)