Rise of Skywalker. Read on to learn more.
During the SDCC 2020 Lucasflm Publishing , Greg Pak revealed that Vader's current investigation into the past will end after the series' fifth issue. Thus far, Vader has visited both Tatooine and Coruscant in his search for the truth, firstly to Tatooine to punish those who made his son "weak". Upon finding none to punish, he goes to the planet of Coruscant to search Pé's old apartment, hoping to find answers and specifics as to what happened to her. After he discovers that security footage is missing, he traces their source to one of Pé former handmaids, Sabé. Not knowing who Vader truly is or what his motives are, she forms a temporary alliance with the Dark Lord in search of the truth. While she had taken the security footage from the apartment, she was unable to decrypt them. Vader can. Together, they head for the planet where Sabé hid the recording: Naboo.
After Vader visits Naboo, he'll supposedly return to his master Darth Sidious in the sixth issue of the series, whom he's been currently ignoring due to his search. As a result, as well as for failing to turn or kill his son, there's going to be consequences for Vader, according to Greg Pak. However, fans will most likely be extremely interested in Pak's next reveal from the :
Vader is going to suffer a terrible punishment and undertake a new journey/quest, and there are key elements that will tie into Episode 9 in a huge way. There's some doors that have been thrown wide open.
Where will Vader be going that ties into Rise of Skywalker and what will his punishment look like?
It's possible that in the works to prolong his life, though Vader might not understand it completely.
While this is just a theory, it would be incredibly epic to see yet another element of Darth Vader's tragic journey tie in to the rest of the Skywalker Sage at large, especially its end.