This was actually a brew that Ali Aintrazi had created, see this article he wrote on how to play the deck: https://www.coolstuffinc.com/a/aliaintrazi-10192018-mastering-rainbow-lich. Essentially an infinite turns combo with Mirari's conjecture, Chance for Glory and Lich's Mastery (to not lose the game), and Banefire from the side being one of the main win cons (copy it with the 3rd chapter of Mirari). Other cards are there to help survive until Lich's master sticks (the article has some nuances of playing the deck).
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Well I agree she doesn't really synergize with the enchantress theme, but she's here as a finisher/win-con. Though I agree that Ajani, Mentor of Heroes is pretty good here as well.