The rarity of Promise of the First Dawn is Mythical, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Promise of the First Dawn is a skin for Keeper of the Light. The skin was added to the game on January 12, 2017, it was created by LaughingSkyPig.
Promise of the First Dawn has been recently added to the game, which makes it rather popular with the game community.