I left the chalices alone since the walkthrough I'm following said I could come back when I have more members so all of them get the sp. However the runes mentioned something about how I must not return to the purgatorium as part of our agreement.
Does this only refer to the final room of the purgatorium?
You just lost the game.
Correct that reference only refers to the final room but I used up that free SP anyways.
After all why return their for free SP x8 PC's when at that time you can just buy the Silver Trumpet Play Devils Aria at level 8 and dragon roar the enemy to death for a max of 200,000 exp per fight.
1 to 2 hours later I had ALL PC's at levels over 100 making the free SP here pointless.
Indeed, by the time your party is full, the free SP in the Purgatorium is hardly worth the trip. I recommend grabbing them on your first trip and using them to level up Purity to gain some early money (especially on characters you don't intend to keep, like Ioshua).
I kept Ioshua in to get Marvelle to join.