Board Thread:Character Discussion/@comment-26340222-20151116200610/@comment-25926288-20151116201426

Merlin and the DO should have the power to kill each other. However, I'll say that not all Dark Ones are equal and have full access to the magic or preach the potential they could have, Rumple was powerful but he rarely ever showed that kind of power. Why? Who knows. Merlin had foresight, but Rumple didn't until he took it from the seer. Maybe each Dark One doesn't fully access the power for reasons. My theory is that the Darkness grows stronger with each successive Dark One, but the magic gets weaker. Emma's strong and the strongest perhaps because she had powerful light magic before hand. But that's for another thread.

1) Perhaps, but I doubt it. Merlin can potentially "kill" the Dark One by putting it back into the Vault.

2) Hook could probably "vault" Emma, but Hook as a Dark One depending on how they are using it, should be either much weaker or on par with her.

I would say they don't have the power og the grail. They have HG magic, but the HG can also cleave themselves of the magic in sword form, which they themselves cannot do alone.