I'm trying to word in a story I'm writing, that the character is showing potential for their [blank]. I'm trying to think of a good word to refer to a promised/reserved title/position for someone that is meant to be second in command, of sorts. Any ideas? Anyone know of a term that would work for this description? Additional details: My main character was turned into a vampire and her sire has "big plans" for her once she has learned the ropes of being a vampire through her mentor. Her sire is pretty much a maniac when it comes to power and is so busy creating his empire, he has his prodigy mentor her. She doesn't realize til later that she is being "formed" into what he wants her to be as the "ideal" second-in-command.