Darth Vader was the 2nd most powerful man in the Empire and he was given the difficult task of wiping out the remaining Jedi Survivors across the Galaxy after Order 66. But in his time not slaughter Jedi and attending to other Imperial affarirs, what did Vader Do?

So in the very early days after his fight on Mustafar with Obi-Wan Kenobi, and him being put into the Vader suit, Vader’s free time was not nice at all. He spent all of it resting and recovering inside of his medical chamber, allowing his burns to heal. During this healing sessions, Vader’s mind was bombarded with regrets, pain and horror at how his life had changed to quickly. He was deeply bitter at Obi-Wan Kenobi for putting him in this position and lusted for revenge at every moment his mind wasn’t focused on the pain.

Soon after, Darth Vader travelled back tothe lava hellworld of Mustafar, and he quickly discovered a cave very strong inthe dark side of the force. This cave contained an ancient shrine created thousands of years ago by a Sith Lord. Soon though Vader became obsessed with this mystical cave and all of his free time was poured into it. He bled his first kyber crystal red here and he soon came to believe that it was the key to bringing Padme back from the dead. Eventually, he asked his master to gift him the entire planet of Mustafar to continue his exploration of the cave and this was granted. Inside he was able to resurrect the ancient Sith Lord who constructed the shrine inside the cave, Lord Momin, who happened to be an artisan and architect during his time. Eventually palpatine alowedhim to begin construction of his fortress and Vader utilized Momin’s architecht skills to build it for him.. Vader then used all of his free time to direct the construction of Fortress Vader, along with installing many chambers and meditation tanks to strengthen his connection to the force.

Eventually though, Vader stuck his ultimate goal and he found the key to immortality… There was a portal which technically lead into the World Between Worlds, and Vader was moments away from using it rescue Padme… but then something utterly cruel happened to him. As is the way of the Sith, Momin entered the portal instead of Vader and claimed his original body from millenia ago, denying Vader access. Now during all of this,

The construction of Vader’s castle though threw the native Mustafarians in the area into total chaos and panic, leading to a disastrous consequence for Vader. The Mustafarians eventually revolted and mounted an incredibly large siege of his castle, and they used Momin’s betrayal to attack VAder lead the closing of the portal… Vader did actually enter, but things went horribly wrong for him… An absolutely cruel twist of fate for the Dark Lord.

Now after this, we can’t move off of Mustafar just yet. Vader also dipped his free time into finding the key to immortality for himself. To do this he investigated the ancient Mustafarian Relic known as the brightstar, which was once owned by Lady Corvax.