I still never really understood what Kingsisle had planned for the finale of Celestia. It really just seemed to meander around for a bit as you adventured around getting the stuff for the grand astrolabe, but then suddenly at the very end they remembered morganthe was a thing. My theory is they wanted to end it at the chancel, but then realized they needed to finish up the grand astrolabe subplot so they just slapped together a random space dungeon from nowhere to finish it up.
The reason Morganthe isn't seemingly mentioned until the very end is because they removed the original prequest to Celestia. In that prequest you learn more about why you're sent to Celestia and a bit more about Morganthe.
As for why you're sent to do the Trial of the Spheres,
Once you collect all three artifacts for the Grand Astrolabe the door to the Trial of the Spheres opens up. Edith Benchley basically wants you to explore the dungeon to learn more about the Celestians/Celestia itself; as well as to challenge yourself and see if you're ready for the trials ahead of Celestia.
I still never really understood what Kingsisle had planned for the finale of Celestia. It really just seemed to meander around for a bit as you adventured around getting the stuff for the grand astrolabe, but then suddenly at the very end they remembered morganthe was a thing. My theory is they wanted to end it at the chancel, but then realized they needed to finish up the grand astrolabe subplot so they just slapped together a random space dungeon from nowhere to finish it up.
There was a lot of things out of place with the lore surrounding Celestia (especially the Celestians themselves). I really wish KI used a gauntlet/dungeon to expand more on the Celestians.
The reason Morganthe isn't seemingly mentioned until the very end is because they removed the original prequest to Celestia. In that prequest you learn more about why you're sent to Celestia and a bit more about Morganthe.
As for why you're sent to do the Trial of the Spheres,
Once you collect all three artifacts for the Grand Astrolabe the door to the Trial of the Spheres opens up. Edith Benchley basically wants you to explore the dungeon to learn more about the Celestians/Celestia itself; as well as to challenge yourself and see if you're ready for the trials ahead of Celestia.
I mean i've done the prequest and all that. I know the backstory to celestia. It's really just that morganthe was kind of....absent from the arc that built her up as a big bad villain. She sat on her throne for about 90% of the world and then the rest of the worlds proceeded to show that she actually is a threat.
actually now that i think of it my problem is actually more that the celestians themselves were relatively underdeveloped as well. we're shown the astrolabe and the Trial of the Spheres and everything, but in the end a grand majority of celestian culture and technology remains unknown to us. We're never given an explanation as to what the trial was meant for, or what kind of race the celestians were (outside of "they liked looking up at the sky", which even then is a bit of an understatement.) Were they a peaceful civilization like (error 404 peaceful civilization in the spiral not found)? were they militaristic like Dragonspyre? I kind of hope we get maybe some sort of interaction with Qyburn (the only living celestian as far as we know) where he explains a bit more of their culture to us. I'm all for headcanons but in this situation i feel like knowing would be better than remaining in confusion.