Iason Heine:
Well, I can't help with Emperor's Key, but the Witness of Dawn... hmm.
The Lords of Dawn have long used that term for their first-their leader. The Leader, the Prima, is the first to welcome the rising sun on theit special occasions, where he witnesses the passing of night into day.
The current Witness of Dawn is a man named Franz, but he doesn't often meet others. I suggest you to go first to the Remple of Einhasad in Aden Town and meet with Priest Wood. He should be able to set a meeting up between the two of you.