Saved by Canon/Playing With

Basic Trope: Character can't die in a prequel since it was established that they are alive in a previous story that took place in the future.
 * Straight: In The Great Story, Bob is alive. In the upcoming Before The Great Story, Bob won't die.
 * Exaggerated: ?
 * Downplayed: Bob was only in a single scene in The Great Story.
 * Justified: Fans don't like it when you toss canon aside.
 * Inverted: Doomed by Canon
 * Subverted: Bob dies in Before The Great Story, his twin brother takes his place and name.
 * Double Subverted: Bob didn't really die, and eventually regains his name and place.
 * Parodied: "Don't worry about Bob's safety, he is in the next show".
 * Deconstructed: When making a prequel, we can't have as many surprises since the fans know what will follow.
 * Reconstructed: Bob has a lot to live up to in The Great Story, so we will just make a prequel instead.
 * Zig Zagged: Bob was killed, resurrected, really killed - we promise this time, before time travel was used to solve the problem.
 * Averted: Bob doesn't appear in Before The Great Story.
 * Enforced: Making a spin-off often means you aren't armed with canon, but you have to follow it.
 * Lampshaded: Bob goes on the front line, because "he is too important to die".
 * Invoked: Whenever a flashback is used.
 * Exploited: The king constantly has Bob doing the dangerous jobs, because prophecy said he won't die.
 * Defied: Screw canon
 * Discussed: ?
 * Conversed: ?
 * Played For Laughs: Bob is constantly told to "Brush it off" any time he gets hurt.
 * Played For Drama: Everything good that Bob did in The Great Story is shown to be for an even bigger evil in the prequel.