10 Star Trek Villains Who Killed The Most

10. Lore

Data's maniacal identical brother Lore was designed with faulty programming that made him extremely unstable.

When Dr. Soong was working on Lore at the Omicron Theta colony, he began displaying signs of malevolence and thoughts that he was better than Humans. This led the other colonists to distrust the android, and they demanded that he be deactivated.

To get revenge on the colonists for rejecting him (and wishing for his death), Lore lured a powerful space creature known as The Crystalline Entity to the colony, where it wiped out most of Omicron Theta's hundreds of inhabitants.

Data, Noonian Soong, and Noonian's wife Juliana all survived the initial attack, though Juliana was severely wounded and needed to have her consciousness transferred into an android body. Though, later (in the episode Brothers), Data and Lore found Dr. Soong (who they both had thought died in the attack) and Lore killed him and stole his newly-designed emotion chip because he still believed that the doctor cared more about Data.