Okay, so let me just confirm all that I have learned so far.
- Zetsu is infinite.
- Zetsu is what powers Manifestations.
- Manifestations have a hard limit, but can be used infinitely.
- Certain Manifestations require knowledge, such as magic.
- Manifestations are unique (?)
Lemme answer this, in order:
- No, one can run out of their reserves (the size varies by person), just think of it as what it actually is, a mana pool. Having "infinite" Zetsu isn't impossible, but is way too rare.
- Yes, and some Youkai abilities as well, but this varies from individual to individual.
- Most have a limit, but it can be raised with training, but as long as you have a reserve of power to draw from, you can use them with little side effects, unless their description states otherwise.
- Well, you require knowledge on how to use any power that you may have, after all most people aren't born knowing how to fight. Magic is just specially complicated, nothing more.
- In a way yes, but it's not like there can't be two people who use fire powers in the world, it's just that each one would have their way of doing it.
Any more questions? Also, to ease things to everyone I'll pin this to the first page as well.