I got a quest from Halstrom that told me to go to mooshu, and I did all the stuff it had me do because I thought I was going to get the level 75 minion from it, and I did a really hard dungeon after trying three separate times I finally beat the dungeon with someone else, and then got the celestia spiral key but it was broken (also, I already went to celestia, so I'm kinda confused on why it had me get the celestia spiral key) so I took it to Halston Baelstrom and he said he'd fix it up and call me back when he's done, what do I need to do to where he'll call me back? I'm pretty confused, explanations appreciated :)
I got a quest from Halstrom that told me to go to mooshu, and I did all the stuff it had me do because I thought I was going to get the level 75 minion from it, and I did a really hard dungeon after trying three separate times I finally beat the dungeon with someone else, and then got the celestia spiral key but it was broken (also, I already went to celestia, so I'm kinda confused on why it had me get the celestia spiral key) so I took it to Halston Baelstrom and he said he'd fix it up and call me back when he's done, what do I need to do to where he'll call me back? I'm pretty confused, explanations appreciated :)
That sounds like Swimming With The Stars (The Spiral Geographic Society Warehouse) but that's in Marleybone not Mooshu...but it does end with getting the blackened, broken, spiral key, which Halston says he can fix...
If that's what you picked up then it is a side quest that used to be a main quest to allow entrance to Celestia. It hasn't been changed even though we can do it after we have the Spiral key.
Anyway, to get your level 75 minion you need to also have done The Runedown for your level 55 spell. To check if you've done that just look for the spell:
Brilliant Light (Life) Virulent Plague (Death) Insane Bolt (Storm) Talos (Myth) Power Link (Fire) Frozen Armor (Ice) Availing Hands (Balance)
If you're level 75 and have trained the school appropriate spell above then Halston should have it for you. If you may have started it and somehow lost the instruction you could check with the Professor in Regents Square.
The first quest you did was introduced back when Celestia just came out.
As you know, it involved us doing a series of difficult battles in order to gain access to the spiral key needed for unlocking the world.
Back then, Celestia was much more challenging than how it currently is; as a result, the battles we had to undertake were supposed to prepare us for the difficulties that lied ahead.
Currently, this quest (the one I described above and you did) is no longer required to gain access to Celestia.
As you also know, just meeting the minimum requirements of being level 44 and completing The Final Countdown Quest will grant you access.
Now, on to your next query.
To learn your level 75 summoning spell. You have to complete a series of side quests first.
Now, the first one requires much more work than the latter. For starters, it is only available when you've been granted access to Wintertusk (side world after completing Grizzleheim).
During your adventures in Grizzleheim, you must complete the side quest given by Baldur in Olde Town. It is available at level 35 and only unlocks after completing quest One in the Snout.
After finishing that quest and learning your new school only spell, you must continue your adventures throughout Grizzleheim all the way up to the final quest "Blood Brother."
The Runedown Quest unlocks (which is another solo school only spell quest) only after venturing about 3/4 of Wintertusk to an area known as Sudrilund.
The latter quest only requires access to Crab Alley; as in, you must beat the area.
That should be it.
Hopefully, this clears things up somewhat for you.
