>>280227617
In part one the tailed beasts didn't even exist. Shukaku was a demon spirit that showed no reaction to Gamabunta transforming into the 9 tails.
Then we're told that the tailed beasts are to be turned into a super weapon so Akatsuki can control all wars.
Then we're shown that putting the tailed beasts into the gedo mazo actually makes the ten tails.
Then the ten tails is actually a tree.
Then the ten tails is actually Kaguya, an alien goddess.
But sealing her doesn't remove the tailed beasts from existence despite them comprising 99% of her chakra.
Kishimoto didn't even consider them that tied to her in the end after all the twists.
Kaguya is on some next level bullshit of retconning.