The Langs are a family of unknown origin which in recent generations has married into the family of Margaret Isobel Thoreaux as well as raising a descendant of Ezra Small in the form of the youngest member of the family, Lana Lang.
Ezra Small was the ancestor of Lana Lang and Henry Small. He was the founder of Smallville and wrote many prophecies of the town's future.
Margaret Isobel Thoreaux was a witch in 1604. She was on a search for the Stones of Power. She and her companions Madelyn Hibbins and Brianna Withridge were burned at the stake for practicing witchcraft. 400 years later, Isobel returned possessing Lana and bringing her two lackeys back to life in the bodies of Chloe Sullivan and Lois Lane. The three witches continued the search for the stones. Isobel was stopped by Clark Kent but resurfaced again in Sacred and Commencement, until finally she was at peace after she murdered Genevieve Teague as revenge for Genevieve's ancestor being responsible for Isobel's death.
Lewis and Laura Lang were the parents of Lana Lang. Laura and Lewis met in high school . They were both killed in the 1989 meteor shower. A toddler Lana Lang watched in horror as the two were crushed under a meteor. Lana soon discovered that Lewis wasn't her biological father (See below).
Louise McCallum was Lana's great-aunt She fell in love with Jor-El (who was calling himself "Joe") despite the fact that she was married. Louise died two days later after a bullet fired by Lachlan Luthor's gun ricocheted off Jor-El's invulnerable chest and hit her in the heart while he was trying to kill "Joe", under the orders of William Tate who wanted Louise for himself. Her husband was framed for her murder but his name was cleared later when Clark pretended to be the ghost of "Joe" and told Tate to confess to being involved with Louise's death. Tate admitted the truth and went to prison.
Nell Potter was Lana Lang's aunt and guardian after her parents died. Nell used to run a flower shop on Main Street, however it was never seen again after the meteor shower meaning it was presumably destroyed. In 2002 she was engaged to Dean Winters and planned to move to Metropolis, provoking Lana to move in with the Sullivans. Nell later attended Lex and Lana's wedding.
Henry Small was the biological father of Lana Lang and a descendant of Ezra Small. He was also once an attorney. He first met Lana in Lineage. Lana and Henry stopped seeing each other after Henry's wife Jennifer threatened to divorce him in Witness, and he hasn't been seen since.