So, I'm sure plenty of you haven't read the Coloss-Eye bios before. Here's a quick rundown of what you need to know for this discussion:
Before the Colossals began creating Monsters, they travelled to each of the 12 newly-formed Elemental Constellations to meet with the newly-born Celestials and teach them music. Each of the 5 Colossals that are now imbued in the Natural islands got assigned their respective Element Celestial. Oh btw here are all of the 13 Colossals if you didn't already know:
Grennitch - Plant island
Frigil - Cold island
Zeffree - Air island
Hyddryd - Water island
Sollum - Earth island
Zarroë - Ethereal island, Workshop, islets
Dulcettéa - Haven, Oasis, Amber
(Also known as Queen Colossal)
[unknown] - Gold island
(Also known as King Colossal)
[unknown] - Shugabush island
[unknown] - Celestial island
Ahymnsa - Tribal island
Lanysta - the Colossingum
Vawldee - Composer island
Ok so now for the actual thing I made this post about. There are still 7 Celestials left unaccounted for, of course, because we haven't gotten any new Coloss-Eyes in a while.
We can safely assume that Dulcettea was assigned Furnoss, seeing how they're basically the Fire Colossal. As for Galvana, while there is no Electricity related Colossal, she IS the leader of the Celestials, so it would make sense that she'd be trained by the leader of the Colossals, the King.
This leaves the 5 Ethereal Celestials. And sure, there are 6 Colossals who are available, there are Ahymnsa the prophet, Lanysta the warrior, Vawldee the composer, whatever the Shugabush one is about, whatever the Celestial one is about and... Zarroë...
Zarroë, the definitive Ethereal Colossal. The mad scientist Colossal. The one that spent millions of years, however long it has been since the Cataclysm, trying and failing and finally succeding in creating the thought-to-be-impossible Workshop Ethereals, and then broke through the fabric of time itself to extend their hands as makeshift islets so that each of the Ethereal Elements can call them home. And that's still not everything they've done!
So I ask you, is Zarroë crazy enough to have willingly taken on 5 Celestials at once? Or did the Shugabush Colossal buddy up with Syncopite or something like that?