Eternal Prison forms a cage around a certain amount of enemies. The standard amount of enemies that can be trapped inside a cage is 2. The targets have to make a Dexterity Saving Throw against 13 or they get held inside the cage until it disappears. The cage dissapears if the caster is unconciouss or decides to let the cage disappear. The standard duration for the cage is 2 rounds. If the target inside the cage decides to escape it gets unconcious for one round and then can escape the cage.
This spell is upgradable by using specific Fragments or using an higher level spell slot.
Increased Scope(10 Fragments or 1 level higher spell slot): This upgrade is stackable. Another target can be trapped in the cage.
Increased Duration(15 Fragments or 2 level higher spell slot): This upgrade is stackable. The cage has another round duration.
Decreased Stamina(30 Fragments or 3 level higher spell slot): All targets stuck inside have to make a Constitution Saving Throw with Disadventage against your Spell Save DC. If failed the target gets paralyzed instantly.
* - (Doom Fury)