Mulligans
General Mulligans
Adaptive Amalgam, Birdwatching, and Trusty Fishing Rod are no-brainers—always keep those. Insight is decent, and there's no need to corrupt it, but it's strictly worse than Birdwatching due to its randomness—and lack of buff. Shadow Visions is a general keep since it can find you Birdwatching, or a buff if you already have it. Apotheosis is the least important of the listed mulligans, but is absolutely a keep if you already have the Amalgam in the mulligan (or a way of getting it).Noticed a lack of Priest decks built around Adaptive Amalgam, so I decided to brew my own. It’s pretty consistent, but it’s hardly a meta player; loses hard to any silence, too, but that shouldn’t be a problem against most decks.
It only runs three minions, so you can reliably pull—and buff—the Amalgam with Birdwatching; of course, there are also the Trusty Fishing Rods to do the same, minus the buff. Fanboy, of which we only run one copy, is in here to give your Amalgam rush, which can provide a crucial edge against many decks. Chillin' Vol'jin gives us access to Birdwatching and the Fishing Rods, but his battlecry can be very useful; for example, if your Amalgam is still poorly statted by the time you draw it and the opponent has a big minion up, you can just steal its stats.
Among the buffs, Divine Spirit is the one that’s really going to transform your dinky 1/2 into a monstrous threat—just wait until it already has decent stats. Before that, you’ll want to look for Apotheosis, which can make you nearly invincible, provided your Amalgam has adequate buffs. Because this deck has no board clears, you’ll really need to rely on that lifesteal from Apotheosis and/or the big taunts from Boon of the Ascended. Boon in particular is great because it doesn’t actually care about silence, as opposed to the Amalgam, which becomes useless afterward.
As for variable inclusions, I think Gift of the Naaru is good (keeps you and your Amalgam alive and draws a card) but not unquestionable. The deck has enough buffs, so that slot really wants to be filled by something like Gift that keeps you alive and/or gets you closer to your Amalgam; perhaps Thrive in the Shadows to find a Birdwatching or Spirit Lash to stall against aggro. If I were to swap it out for another buff, I would choose Power Word: Feast.