Sith wayfinders were a pyramid-shaped artifacts created by the ancient Sith as a means of navigating challenging stretches of space. Wayfinders were created through the study of the brains of purrgil, space-faring megafauna who could travel through hyperspace by biological means.
We learned from Star Wars: Episode IX - The Rise of Skywalker (2019) that, by the time of the First Order-Resistance War, at least two Sith wayfinders existed. One, belonging to the Sith Lord Darth Vader located on Mustafar and the other one belonged to Lord Darth Sidious located in the second Death Star. Both Sith wayfinders pointed the way to the legendary Sith redoubt of Exegol.
According to human historian Beaumont Kin:
"Sith wayfinders. Ancient things. There were always two. One for the Sith master, one for the apprentice."
Assuming that Vader and Sidious' wayfinders could have been passed down to them through the generations of Sith Lords as the only way to get to the secret Sith planet of Exegol, logic dictates that the two mentioned wayfinders originated as twin artifacts from Darth Bane's Rule of Two, but, is that true?