Board Thread:Spoilers!/@comment-4936165-20140827005907/@comment-24674051-20141110152530

I would say that Emma, like her father before her, defeated Mal, enough to complete the task (David to plant the Egg, Emma to Retrieve it). The wounds that were dealt were probably not enough to kill her Dragon Form (at least not permanently). I think the curse on Mal was such that she was defeatable, but not killable, except with the Failsafe device which kills everyone.

When Regina undid the original curse, that is what released Mal from being stuck in Dragon/Spectral/unkillable form. She probably went and stayed out of sight during the "lost" year, and was pulled back to Storybrooke in the more "normal" fashion with Snow's curse. Even from the flashbacks in Season 1, the Mal that exists around the time of the curses seems to be more reclusive, prefering to live a relatively quiet life in solitude.