The Vampire Diaries

John Gilbert is Grayson Gilbert's younger brother. In their youth, his brother taught him about the vampires through the jounrnals of their ancestor, Johnathan Gilbert. They also inherited a ring each that prevented them from being killed. John had a crush on Isobel Saltzman and he was the one who sent her to Damon Salvatore when she wanted to become a vampire. After her transformation, Isobel found John and they formed a partenship to get their hands on a mysterious invention created by Johnathan Gilbert.

John arrived in Mystic Falls for the Founder's Day and was shown as a member of the Founders' Council. However, he knew that Damon was a vampire, that there had been a tomb under the Fell's Church and he knew about Katherine. He tried to intimidate Damon into helping him find the invention but Damon threatened to kill him and everyone on the Council. Along with Alaric Saltzman, Damon discovered that John was keeping an eye on the vampires who had been in the tomb. Soon, he confronts Pearl about her possession of the invention but Pearl has already given it to Damon. John kills Pearl and Harper after this. When Isobel returns to town, John finally gets the invention at which time it is revealed that Isobel and John are working for Katherine and that they are planning to kill the tomb's vampires. Unofficially, their goal is to kill the Salvatore brothers and save Elena from suffering in a life filled with vampires. It is also revealed that John is Elena's father.