Scott Rhonson
Scott Rhonson is the son of Lily Van Der Woodsen and Rufus Humphrey. He is revealed in season 2, and it is shown that Rufus was unaware of this son. Scott is the half brother of Serena and Dan and it's awkward since they got married... Anyways, Scott shows up and NYU in season 3 and he starts dating Vanessa. He then shows himself to Rufus and they start to get along. Then after Lily and Rufus decided to get married, Scott went to their wedding where he saw his two parents fighting and saying they didn't want to get married. Lily then yelled at Scott and he ran away. Around the end of season 3 it is shown that Georgina found Scott, but he was never shown in the TV series again.