Same conclusion I reached. I imagined that the Lavos species emerged from a planet which, in its maturity, became aware of some...entity of oblivion. Like, imagine something with sentience on level of the planet, except not a giant chunk of rock. And this thing would bring about the end of the space-time continuum itself...
So, they designed Lavos to scour the universe and produce an evolutionary singularity -- the biological pinnacle of elemental power. This being would return to challenge the villain.
Still, that sounds pretty cold, and the idea that some civilization couldn't produce something better than that given a series of 65 million years is farfetched.
~
So, differing from that, Lavos could be written as an attempt to create God. Again, by decimating planets and absorbing their energies and inhabitants' genetics, an evolutionary singularity would be reached, like a maximum sentience. Except there's an issue...the Lavos candidates do not like this once attaining sentience. Their cold voyages across the voiceless stars; their solitude, and loneliness nesting in the chaotic hearts of planets; the slaughtering, massacring, and brutality required of their mission...they would grow to hate their creators and the universe, and only desire a single thing.
Lavos reached a fast track through the extraordinary events of the Chrono series, obtaining a position in the Darkness Beyond Time allowing the consumption of the space-time continuum itself. And Lavos was defeated in this regard. But eventually, after all the Lavos candidates perish, millions of years from now...there will only be one remaining: the singularity. And it will try to destroy the space-time continuum once it feels it is the final Lavos.
Still, that's really cold and not "Chrono", so who knows. Part of the attractiveness of the franchise is that it's limited to a single planet or even a set of islands. To introduce space might be a good or a bad thing...
