Darth Vader is a Sith Lord. He has a lightsaber. He is strong in the force. His force telekinesis is strong enough to move large objects without lifting a finger. He can sense thing from far distances. His favorite force ability is the grip (choke). His cybernetics allow him super strength. Even though the cybernetics hinder his speed, he makes up for it with the force and his fighting style, which focuses on heavy blows.
The team to stop him
The team to stop Darth Vader consists of Thor, Batman, Pr.X., and GL John Stewart.
Thor- able to match Darth Vader's speed and strength. Mjolnir can fend off his lightsaber and any force throw.
Batman- able to outwit the Sith Lord and has the tech to short-circuit his cybernetics.
Professor Xavier- being the most powerful telepath in Marvel, he is able to make the team mentally invisible to Vader.
Green Lantern John Stewart- able to match Vader's strength, speed, telekinesis, and saber. Also, GLJS has military experience that can match the Clone War veteran.