The term 'Star Trek Villain' can be broken down into three crossword solutions: KHAN (4 letters), Klingon (7 letters), and Romulan (7 letters). KHAN is a genetically engineered superhuman from the late 20th century who was revived by Admiral Marcus in the 2013 movie Star Trek Into Darkness. The Klingons are a warrior race from the Star Trek universe, often portrayed as antagonists to the Federation. The Romulans are a humanoid species from the Star Trek universe, also often portrayed as antagonists to the Federation.