I don't trust The Key, especially after Miayli's words of caution. I don't think Azem made The Key, but I do think they may have been in possession of it at some point. If that's the case, then I think what happened with them in the past is repeating itself now with the Warrior of Light.

Some speculation

Miayli told us that info about The Key is back in Alexandria, and so I think we're gonna learn about where the Millala are originally from before settling the South Sea Isles, and where they got The Key, and that will be the setting for 8.0.