A Death Knight is Your Friend!

Bornakk reminds us about Death Knight lore we should already know from the Lore & Quest panel at this year's BlizzCon:
The idea is that a character goes to become a Death Knight, is trained as a Death Knight, but then realizes they doesn't want to go through with the evil acts they are instructed to perform. So the character finds a new Alliance or Horde home who accept them as a necessary evil (like warlocks) to help them fight their enemies.