John Gilbert is extremely shady. He was always known to Elena and Jeremy as "Uncle John"; however it becomes known that he is actually Elena's biological father. He hates vampires and does anything he can to protect Elena from them.

At the end of season 2, John sacrifices himself to save Elena. He also writes her a letter apologizing to her for everything he did in the past, and leaves his protection ring for Elena to give to her future child.

Vampire Diaries Quotes

Break out the popcorn, Blondie. Elena’s little sex romp isn’t over yet.

Enzo

You want a love that consumes you. You want passion and adventure, and even a little danger... I want you to get everything you're looking for. But for right now, I want you to forget that this happened. Can't have people knowing I'm in town yet. Goodnight, Elena.

Damon