How do you become a death knight?

You have to install Wrath of the Lich King and all the WoW expansions before that. You log into your account and go to the create a character. Under every race there should be a death knight option for class. However, you MUST have a character that is level of 55 in order to create a death knight. This is because the Death Knight is a hero class. If you don't have lich king or you don't have a level 55 you can't have a death knight. And you don't BECOME a dk you create a dk. [YOU CAN ONLY CREATE ONE DEATH KNIGHT (DK) PER SERVER]

If you want to become a death knight, stand at your window in the full moon, climb onto your roof once you see it, then shout out: I OBEY THE LICHKING! I SHALL KILL ALL HUMANS AND OTHER MORTALS IN MY QUEST TO BECOME HIS MOST TRUSTED SERVANT!