Zig Zagged: Jack is killed by murderers, but Jill feels no obligation to avenge him...until she's trained. But she was going to train anyway - his death wasn't a motivating factor in her desire for training.
Averted: Jack dies in an accident, and no one can be blamed. She mourns and lives on normally.
Enforced: "I've run out of ideas for Jack-centric episodes. Let's kill him off and allow a newer hero to take over."
Lampshaded: "No! Jack is dead! Now Jill must take up his sword."
Invoked: Jack is a Decoy Protagonist whose role as a protector to Jill hinders her as much as helps her. He knows that the only way for her to reach her full potential is for him to die.
Defied: Jill does not want to take up Jack's sword
Discussed: Jill took up Jack's sword.
Deconstructed: Jill feels obligated to avenge Jack but has no training to back her up or natural skill with which to fight. She gets slaughtered as soon as she starts fighting.
Reconstructed: After getting her ass kicked enough times, she starts training and becomes badass enough to handle things on her own.