Honestly, if Genndy is going to acknowledge time paradoxes, both Old Jack and Ashi should have ceased existing (had Aku died in the past, Jack would never have had any of the experiences he did while in the future, including traveling back in time to stop Aku). And young Jack should either cease existing as well or wake up in a timeline where everything is normal.
Also, this reminds me, so Aku eventually stopped using his little fire TV to watch Jack when he realized that Jack wasn't aging and he was overcome by depression, right?
Only, Jack lost his sword almost moments after Aku destroyed the last time portal. So wouldn't he have known that Jack no longer had his sword and would have been helpless against him, which would lead to Aku killing him?
Gender: Male Location: In Luna's mane, chasing STAAARS!
So if everyone knew Jack was going to go back in time and change the past, does that mean Scotsman was ok with the chance of his daughters no longer existing? That doesn't seem right. That doesn't seem right at all.
More of a Time Remenant. The whole timeline unravels and no one exists anymore.
Basically, under that model, Old Jack destroyed his universe.
..maybe. When Byrne wrote Superman and Etrigan traveling to the past to stop Morgan Le Fey from creating a piece of jewelery that infected a woman and turned humans into living towers, taking over the city, his answer to this problem was having Supes move his body in front of the spell that created the artifact, which should have killed him.. Instead, time reset to him never having traveled back in time, because the artifact was never made.
Dumb question. Did ashi's power fix the stop aging thing? If Jack still technically exists outside of time or whatever, that gives him free reign to mess with time with no personal consequences. Just a thought.
Odds are, Aku killed him. Nothing else could probably do it except an immortal, invulnerable sorcerer with only one real weakness (No reason to believe Guardians weapons, Scottsmans claymore, or anything else could do more then slow Aku down.)
Remember the Guardian didn't just use the portal like a crystal ball, but that someone seemed to speak to him through it. It's why he stopped beating on Jack.
So it could be the gods were just lying to him. "Yeah, guard this portal because Jack has a destiny, and you'll die in glorious battle! Would we mess with you? *Whispers* Can't wait to see the look on that assholes face when Aku kills him like a chump."