Curtis Knox is an immortal doctor, warrior and killer in the WB/CW TV series Smallville. He served as the main antagonist in the seventh season episode "Cure".
The man known as "Curtis Knox"'s past was shrouded in mystery. At some point in his life, he acquired immortality and lived through the ages fighting Mayan warriors and Crusaders but he always survived.
By the 1800s, Knox moved to London where he killed several prostitutes whom the public dubbed him as "Jack the Ripper". During World War II, Knox traveled to Germany and became involved with the Nazi party. At the turn of the millennia, Knox came to America and married a woman named Sophia.
During his eternal life, Dr. Curtis Knox became a brilliant neurosurgeon who developed a cure for meteor freaks by simultaneously removing all of their memories of having powers. In actuality, he was obsessed with trying to make his wife Sophia immortal by harvesting kryptonite-infected body parts from meteor freaks that he would then transplant into her body.
One of his patients was Sasha Woodman, a metahuman who could control bees, returned to Smallville and ran into Chloe Sullivan who confronted her and asked how she escaped Belle Reve. Sasha claimed that she was cured and said she doesn't remember the last six years because she underwent a procedure by Dr. Curtis Knox. Sasha leaves towards her car and was approached by Dr. Knox himself. He tells Sasha she has "something he needs" and presses a chloroform-soaked handkerchief to her face. Sasha passes out and Knox drags her away.
Lex met Dr. Curtis Knox in the library of the Luthor Mansion. They have been working together to cure metahumans, but Lex asks him about some questionable tests Knox has been running on Level 33.1 subjects that Lex never approved. Knox blows off his concern, claiming that science and medicine only advance when risks are taken. Lex asked if Knox knew where three missing patients were and Knox suggests that their memory loss might have made them disappear. He thinks Lex erased their knowledge of Lex's responsibility, but Lex claims he was helping them by eliminating disturbing memories and Knox exits.
In an elaborately-decorated bedroom, Knox is seen caring for an unconscious woman. She is surrounded by jars containing green glowing liquid and life-support machinery. He kisses her and reports that he has found another "puzzle piece". He puts on an apron and approaches Sasha, who is strapped to a table, struggling to get free. Knox selects a surgical instrument and extracts an organ from Sasha's abdomen, killing her.
Chloe Sullivan researched Dr. Curtis Knox at the Daily Planet. She then went to his clinic and announces that she wishes to be cured of her meteor-rock infection. Lana Lang had also done research on Knox discovering his work with meteor-infected people.