- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
Anaphasic life form who allegedly originated on Earth in the 17th century. Ronin formed a symbiotic relationship with Jessel Howard, an ancestor to Starfleet officer Dr. Beverly Crusher, and continued his relationship with the Howard women up to Beverly's grandmother, Felisa. Ronin was killed in 2371 by Beverly Crusher when his true, deadly, nature was revealed.