Ardra posing as Satan in 2367
The devil (also known as Satan or Lucifer) is a malevolent entity from Christianity as depicted in the Bible.
In 2254, in an illusion created by the Talosians, Christopher Pike referred to his horse Tango as you old devil. (TOS: "The Cage", "The Menagerie, Part II")
When Khan was exiled to Ceti Alpha V by James T. Kirk, he referred to a passage from Milton's poetic dramatization of the story of the Devil's fall from grace, Paradise Lost, in which the Devil states that it is "better to rule in Hell than serve in Heaven." (TOS: "Space Seed")
In 2267, Matthew Decker compared the Planet killer to the Devil. (TOS: "The Doomsday Machine")
Lucien, a Megan from Megas-Tu, lived on Earth during the late medieval and early modern periods, between the 13th and the 17th centuries. In 2269, the Enterprise crew visited Megas-Tu and were tested with an elaborate ruse to determine if their attitudes had changed since the times of the Salem witch trials in 1691 where the Megans were persecuted. During the ruse, the Megans claimed that Lucien was known on Earth as Lucifer. Later, the crew of the Enterprise wondered if Lucien really was the same being as Lucifer. (TAS: "The Magicks of Megas-Tu")
Other religious characters resembling the biblical Devil included the Klingon Fek'lhr, the Ventaxian Ardra, the Drellian Torak and Mendora in the Berussian Cluster. (TNG: "Devil's Due")
On Omega IV, an entity known as the Evil One was cast in the same light as the Devil. Captain Ronald Tracey, in violation of the Prime Directive, tried to trick the Yangs into thinking that Spock was the Evil One. (TOS: "The Omega Glory")
In 2286, the Klingon ambassador compared James T. Kirk to the Devil. (Star Trek IV: The Voyage Home)
In describing Ardra to Captain Picard, Doctor Howard Clark described her as being "for all intents and purposes, the devil," that the people of Ventax II literally believed they'd sold their souls to devil. Later, while demonstrating her abilities to Captain Picard and Lieutenant Worf, the impostor posing as Ardra transformed into the Devil and Fek'lhr. Picard, however, stated that "I have encountered many who more credibly could be called the devil than you." (TNG: "Devil's Due")
In 2369 after Vedek Winn Adami accused Commander Benjamin Sisko and the Federation of living in a dark universe into which they wanted to drag the spiritual Bajorans into, Sisko replied that the Bajorans who lived and worked with the Federation officers aboard the station for months could prove that they were not the Devil. (DS9: "In the Hands of the Prophets")
In the theology of the Bajoran religion, the Kosst Amojan plays an analogous role to the Judeo-Christian Satan and the Pah-wraiths to his fallen angels, the demons.
Captain Kathryn Janeway compared her unholy alliance with the Borg to, "a deal with the Devil." (VOY: "Scorpion")