Padmé could be a main character. Since Darth Vader is without his suit, it could be a scenario where he's reliving memories of her, and she could appear as a Force ghost or in his dreams, guiding him in some way. Another character could be Obi - Wan Kenobi. Their relationship was complex, and without the suit, Vader might be more vulnerable, and Obi - Wan could try to sway him back to the light side.
One possible plot could be Naruto being transported to a Star Wars universe. He finds the Vader suit and decides to put it on for some unknown reason, maybe thinking it gives him some sort of power boost. With the suit, he starts to learn about the Force in a very Naruto - like way, using his own ninja determination and chakra control to manipulate it. This causes chaos as the Sith and Jedi are both confused by this strange new entity in their midst.
Darth Vader's new suit was a marvel of Sith engineering. It was darker, more menacing than ever. The black armor seemed to absorb all light around it. The red glow of his eyes was intensified, making him look even more terrifying. With his new suit, he moved with a newfound grace, his every step sending a shiver down the spines of those who beheld him. His new suit also had enhanced weaponry, a lightsaber that was more powerful and a wrist-mounted blaster that could take out multiple enemies at once.
One idea could be exploring Darth Vader's identity before he became encased in the suit. Maybe he rediscovers his old self and tries to reconnect with his past relationships. Another could be him having to face the Jedi without the intimidating suit, relying solely on his raw Force abilities.
Sakura could be one of his allies. She would be initially shocked by Naruto's new look in the Vader suit but would quickly realize it's still him. She could use her medical skills to help Naruto if the suit has any negative physical effects on him. Another could be Kakashi. He would be very intrigued by the suit and would use his wisdom to guide Naruto in controlling whatever new powers it gives him.
In some fanfictions, Darth Vader's upgraded suit might have enhanced weaponry. For example, it could have built - in lasers that are more powerful than the standard ones. This would make him even more formidable in combat.
In a fanfiction, the new suit could have a telepathy enhancer. This would enable Vader to read the minds of his enemies more clearly and from a greater distance. Additionally, the suit might be equipped with a shield generator that could protect him from both blaster fire and lightsaber strikes. The design of the suit could also be more aerodynamic, allowing him to move faster in combat situations.
Well, Naruto would look really cool in Darth Vader's suit. He might use the suit's features in his own ninja - like way. Maybe he'd use the built - in breathing apparatus to his advantage during a difficult fight, like when he's facing a really strong enemy and needs to focus on his chakra control without being distracted by things like smoke or lack of air.
Well, one thing that could happen is Naruto would look really out of place yet super cool. He might start using the Force in his own Naruto - like way. Maybe he'd use it to enhance his shadow clone jutsu, creating even more clones than before. It would be a strange mix of the Star Wars and Naruto universes, and his friends in Konoha would be both shocked and amused.
A possible plot twist could be that the suit has a mind of its own. Since it's from the Star Wars universe, it might try to influence Naruto towards the dark side, but Naruto resists. Another twist could be that Naruto discovers a hidden power in the suit that has nothing to do with the Force, but is related to some ancient Jedi or Sith knowledge that can be applied in the Naruto world in a unique way.