Build-times lorewise.

[Zero]

But (STILL MORE SPOILERS)

Hidden Content:

they don't consume all Protoss and Zerg lifeforms anymore, right?

Dark Templar Twilight Spoiler:

Hidden Content:

No, at this point it would seem that their work is done, which is why all of the ones that were still remaining in temples left, and all met at this one central point. Which is where Zeratul went to investigate the meaning behind it all.

[Shadow Archon]

I meant the energy creature from Shadow of the Xel'naga. It could have just dropped off some of the captives and left for the temple. But thats assuming Duran has a connection to the energy creatures, which is unlikely.

[Norfindel]

Dark Templar Twilight Spoiler:

Hidden Content:

No, at this point it would seem that their work is done, which is why all of the ones that were still remaining in temples left, and all met at this one central point. Which is where Zeratul went to investigate the meaning behind it all.

Interesting. Probably we're going to learn more about that in the Protoss mini-campaign (level?), then.