Kane Skywalker (Destiny)

Darth Nemesis was a Human male clone of and a Sith Lord who served the Dark Lord of the Sith Darth Vorath.

Creation
Upon the ascension of and his apprentice, Darth Vorath realized that he would need to be prepared in case the two Sith found out about his operations. Knowing Vader in particular was strong, being the foretold Chosen One, Vorath sought out a sample of Vader's DNA and brought it to the Kaminoans, who created a batch of clones for him shortly before being executed by the Dark Lord, who did not want any word to leak out to Sidious.

After putting the clones through a series of trials and tests, Vorath eventually found one that had none of Skywalker's weaknesses -- primarily his love for those he held dear -- as well as none of the cybernetics that now hindered Vader. Satisfied that he now had a weapon that could take down Sidious' apprentice should the need arise, Vorath named this clone Darth Nemesis and made him one of his top agents, along with the Zabrak Sith Darth Ravage, whom Nemesis would frequently be partnered with.