Create An Army Of NPC Guardians With Priest Class Order Hall Item (Patreon)

The Priest Order Hall class upgrade "Altars Of Blessing" allows the priest to use an item from either a shadow or light altar. One of the items the shadow altar produces is the "Vial Of Dark Shadows", which summons a large, tentacled "Faceless One" for ten minutes. The faceless ones have quite a large health pool and does respectable damage, it is designed for tanking bosses. 

The altar items are only meant to be used once per day. However, I noticed that when I "opened" but did not pick up the vial it was subsequently sent to me in the mail. The next day I picked up the same item from the altar and used it, then used the vial in my mail. Both Faceless Ones appeared. 

There doesn't seem to be any limit to the number of faceless ones you can get with this trick, though as a random drop it is probably going to take me a while to create an army.

Very likely this will work with other class order hall items-I am testing this currently.