Wanting revenge, Lex uses a kryptonite bomb to have Lana's stolen bio-enhanced suit, designed to absorb and emit kryptonite radiation, absorb the radiation to de-activate the bomb and subsequently never be able to go near Clark again without fatal effects.Oliver Queen (Justin Hartley) discovers Lex's location and uses a bomb to blow up Lex's travelling medical transport, seemingly killing him.Season three revealed why Lex endured Lionel's harsh parenting; his father blames him for his younger brother Julian Luthor's death, however, Lex took the blame to protect the true killer, his mentally unwell mother Lillian Luthor (Alisen Down), from Lionel's wraith.
When Clark discovers the Kawatche Caves, under a Luthor Corp construction site, Lex opts to be the curator of the caves to preserve them after he notices symbols on the cave walls that match the symbols on the disc, as well as an octagonal shape in the wall of the cave that would fit the disc perfectly.
His interest grows more and more when he finds Clark constantly in the caves, and later with a piece of paper that appears to indicate that Clark has deciphered the language on the cave walls — although, Clark denies being able to read the language.
Season seven displayed Lex's descent into darkness; he has a brother-like relationship with Grant Gabriel (Michael Cassidy), the new editor of the Daily Planet newest editor, until it's revealed Grant is actually a clone of Lex's late brother.
Lex then discovers that the previous symbols are connected to the secret organization Veritas, which his father is a part of.
As the series unfolds, Lex's curiosity about Clark and all things connected to Clark ultimately destroys their friendship.