How would I set up a magic system for my world where a really strong seal (or a magic lock) for a really bad character has a key that can open it? What explanation can I tender for a seal that is never meant to be broken having a way to be broken?
closed as off-topic by Mołot, Pavel Janicek, Renan, Cadence, StephenG Dec 14 '18 at 11:04
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "You are asking questions about a story set in a world instead of about building a world. For more information, see Why is my question "Too Story Based" and how do I get it opened?." – Pavel Janicek, Renan, Cadence, StephenG
Because to be good, you have to be a little naive, you have to repress the cynicism grown of hard experience. One of the defining characteristics of the unquestionably "good" faction is that they have to believe that even the great evil can repent and accept the right and correct order of things.
That means that no prison can be forever, the option to open the prison and let the now reformed evil out into the world has to be maintained. To lock someone up forever would be taking a step across the line to evil themselves.
The Seal was not originally intended to be permanent and comes with its own means of undoing so that anything banished may be recovered.
Magic cannot perform permanent feats, when a spell is cast, it comes with an assumption that it will last only as long as the spell is understood to be needed. The Key is a semi-metaphorical promise that the spell is still needed, without which the seal will fail eventually.
The Key is a direct manifestation of the Seal into our dimension, linking the magic of its creators to the seal itself so that the spell will not eventually degrade and fail.
The Spell's creators have moral qualms and were unwilling to outright kill their foe, only to banish them. Destroying the key seems too much like killing the foe since without it they can never ever return to our dimension.
The big bad is indestructible. Killing it would trigger resurrection or reincarnation, where imprisonment keeps the bad guy contained. The "key" does not necessarily have to be an intentional way of letting the big bad out, but recognition of a weakness of the containment.
The big bad is favoured of gods, goddesses, or other powerful creatures. While those more powerful beings recognize the big bad has gotten out of line, and they will tolerate confinement with an indefinite term, they will not allow execution or permanent confinement.