As Gough explains, by the end of the sixth season, Lana has shown that she can beat Lex at his own game.
Over the course of the show, Lana transitions from the girl next door to a more "self-reliant young woman".
In the episode "Requiem", Lana discovers that her suit absorbs kryptonite, but also emits the radiation making her a potential danger to Clark.
The resulting death of Genevieve, who was revealed to have been the cause for Isobel's death centuries prior in the episode "Bound", When she learns that Lex set up a fake pregnancy in order to get her to marry him in the season six finale "Phantom", Lana effectively ends the marriage and fakes her own death to escape Lex after he threatens her.
She also frames Lex for her murder, to punish him for his betrayal.
Her obsessions also begin to affect her relationship with Clark by the episode "Wrath".
Eventually, Lana realizes that, even though she loves him, the only way for Clark to help the world to the best of his ability would be if she left Clark and Smallville for good, which she does in the season seven finale.
In the first season, Lana and Clark Kent (Tom Welling) are just beginning their friendship, as she is a popular cheerleader dating star quarterback Whitney Fordman (Eric Johnson), and Clark cannot get near her without getting sick from the kryptonite necklace she wears.
In the pilot episode, when her parents are killed in the first meteor shower, Lana is adopted by her aunt Nell (Sarah-Jane Redmond).
Initially, Lana is characterized as the intelligent "girl next door".
She eventually becomes a tragic figure in Smallville, as the decisions made by Clark and Lex change the character over the course of the show.
As the first season progresses, Lana grows closer to Clark, while Whitney begins to distance himself because of his father's medical ailments.