Lila West was a character and a main antagonist in DEXTER. Serving as the primary antagonist of Season 2. She is a Sponsor for a Narcotics Anonymous Group for various types of addicts, having claimed to overcome her own vice: pyromania. She worked as an artist, often stealing items to use in her work and had a very abstract (if not somewhat disturbing) sense of style with her projects.
She meets with Dexter Morgan after he commits himself to the group in spite of his girlfriend Rita Bennett, appeasing what she thought was an addiction to heroin following a realization about her now deceased ex-husband Paul Bennett. In some way Dexter sought to understand his Dark Passenger and potentially overcome it, but upon meeting Lila he delves deeper into the dark and forsakes a number of things in his life for her (including a breakup with Rita). Eventually, however, Dexter realizes that she is a sociopath who hangs out at recovery meetings to vicariously experience emotions she is incapable of feeling.
While initially sparking a romance with Dexter, it's shown that she has a violent response to betrayal and is not above exploiting others to her needs (even going so far as to light her apartment on fire to draw Dexter closer to her). Her manipulative nature wards Dexter away, realizing that she was "poisoning" his life and she even frames Angel Batista as a date rapist-abuser as part of her diabolical thinking. Her pyromania results in the death of James Doakes as well as a former boyfriend, additionally nearly killing Rita's children Astor and Cody Bennett (also endangering Dexter himself) and he finally decides that Lila has to be "taken care of", ending in her death in Paris, France. Ultimately, she's revealed to be the Main Antagonist of Season Two, alongside secondary antagonists Sergeant James Doakes (whom acts as a primary) and Special Agent Frank Lundy. She is the first antagonist to kill a main character, James Doakes while others would follow suit in later seasons. She's also the only lover Dexter has killed, where he spared both Lumen Pierce and Hannah McKay.