Consider that the Nu could actually be the 'Entity';
Exhibit A:
All life begins with Nu and ends with Nu.
This could be rephrased as 'Nu is the Alpha and the Omega'
Exhibit B:
Nu are present in most if not all time periods, probably 1999A.D as well, but there isn't enough info, anyways.
This is *highly* improbable if described by natural existence and impractical for Belthazar/Gaspar/Melchoir to do so. The third, and my theoretical proposition, the Nu are temporal transcendent, suggesting higher, god-like, even magical properties.
Exhibit C:
The Nu 'tend' to follow/wait for the Gurus/Crono & co. and aid them in their quest to save the planet/Schala.
This one is more hypothetical, but still has some logical basis.
Exhibit D:
The Nu group in large amounts in Zeal; suggesting an era/area of import.
Coincidentally this is when the Gurus start their efforts to stop the 'awakening' of Lavos, a severe threat to the Planet/Entity.
Purely speculative suggestion: the Nu have a collective consciousness across space-time bound by 5-D time(Time- Error). Allowing the Gurus, specifically the ones around Nu; Gaspar and Belthazar to 'know'
que pasa.
Just a theory, anyways; thoughts?
I've always got the feeling that the Nus, while most likely friends of the planet, were not actually a naturally occuring creature. That is to say... the first alien invasion on the Chrono planet. Even though they've been around since prehistoric times, they're usually referred to as strange, out of place creatures. Even the Black Omen seemed normal to folks.
Like the Chu-chu in Xenogears? I believe the game(XG) said that they were other-worldly...