Thunderbolt: Oh, Lightning, this is just about the greatest thing ever! I've always wanted to play a big death scene! The selfless hero who sacrifices himself to save the innocent. I'll kick bigger than Old Yeller! So, how do I make my shockingly unexpected and triumphant return?
Lightning: You don't.
Thunderbolt: What do you mean, I don't?
Lightning: You don't make a shockingly unexpected and triumphant return. You die. You're dead. You never come back.
Thunderbolt: Not even for a reunion show?
Lightning: Not even for a cameo in the remake.
Thunderbolt: They're writing me out of the show?
Lightning: They're gonna replace you with a younger dog.
Thunderbolt: So that's what those auditions were really all about!
~ Thunderbolt and Lil' Lightning, discussing the fate of their show

Characters which their ultimate fate is unknown; the last time they were seen, they were in situations where it's unusual to survive, but since they weren't seen dying or their bodies or remains weren't found, there is a possibility that they survived.