Info on new characters arriving in Season 4

"For episode 4.01, the character Pastor Young is being cast. His daughter April Young is also being cast in a recurring role beginning in episode 4.02. Pastor Young hates vampires, and he threatens Meredith that he will expose her use of vampire blood on her patients and he captures Damon and wants to use him as bait in order to try to capture Stefan, too.

April Young returns to town after her father dies, to attend his funeral.

Connor Owens is also being cast for episode 4.02. He shows Damon a folder of notes he's been keeping and threatens Damon. Connor and Tyler argue over each of them having something that the other wants (knowledge of how a curse is triggered and the location of a particular stone)."

Courtesy of Spoiler TV