User blog comment:EmpyreanSmoke/Supernatural Q&A (Closed)/@comment-172.101.67.105-20151115181722/@comment-24834479-20151115200730

1. God and the archangels beat back the darkness which weakened it, enough so that they could lock her away. He created the mark as a lock and key, to bind the darkness, but in order for it to do that it had to keep her weak enough to be bound. The mark absorbed her own power and energy, not allowing her to heal, but getting more powerful itself.

2. As a force older than God, we thought of it as literally unkillable, but now that we are writing it as God's sister, we are figuring out where her mortality lies.

3. With the powers he had potentially, yes.

4. It depends on how strong the seraph is.

5. It would be a challenge, but a Grigori could beat an archangel in some scenarios.

6. I hope they do.