DECKBUILDING NOTES: As much as I love Mentor, and as much as he wins almost every game I land him in, he's a bit slow given our manabase. I'm looking to cut one, and if you have any idea of what I should put in instead-- good tempo disruption, specifically-- please do suggest.
So. This is a Young Pyromancer/Monastery Mentor deck using Voice of Resurgence as an additional powerful threat and a nuisance vs Instant decks, a Glittering Wish board for answers to a myriad of problems Modern might throw at us, and several cheap and free versatile spells such as the DTK Commands and some charms. We're sticking to Naya colors and keeping ourselves as strong as possible to that scourge of Modern, Blood Moon, with a slim manabase and Manamorphose, which also gets value off of our Young Pyromancer and Monastery Mentor while deckthinning and making our colors less punishing. The Miser's Mutagenic Growth can occasionally surprise someone into an unfavorable trade or Mental Misstep a Bolt targeted at an important unit, and sometimes just lets you swing for a surprise win.
Gods Willing and
Faith's Shield
are metapicks, mostly. If a lot of decks in your meta reduce you to 5 and then kill you, Faith's Shield is both good protection for your important creatures for cheap, AND a good way to Angel's Grace out of nowhere. Notably, a Grapeshot for a million doesn't actually win through Faith's Shield; you just cast it when you have 5 life, name red, and the rest of the copies get countered. Gods' Willing gives much-needed filtering, much like Horizon Canopy, which is one of the best cards in Modern.
The deck can be rather explosive with Atarka's Command with its token generation, and Dromoka's Command mainboard is one of my favorite additions to the deck, it being one of the most versatile cards in modern.
The sideboard is self-explanatory, but I think it's very close to the most optimal wishboard possible in our colors:
Dromoka's Command #4 gives us a fetchable answer to indestructible enchantments like Keranos, God of Storms, a fetchable fight card and a pseudocounterspell for Bolt;
Atarka's Command #3 gives us a way to deal lots of damage with a gummed-up board;
Boros Charm does 4 damage on an empty board, and makes us wrath/pyroclasm resistant;
Firespout cleans up problematic boardstates, with an additional option to not pay red mana and avoid hitting our own things;
Fracturing Gust may as well read 'Destroy target Affinity player. They can't be regenerated.', but be warned that you can still be mised by an inkmoth nexus after casting it, so Glit Wish for it on turn 4 with a removal spell up in case they switch to that plan, and be wary of Thoughtseize.
Titanic Ultimatum is the greatest swag possible in a deck like this, and it can be fetched both as a bad manner play to show off your bling, and also just to win against gummed-up boardstates like big Zoo.
Guttural Response
helps us win STACK WARS in the lategame against blue decks, as well as be saved to make Cryptic Command look like a very bad Magic card;
Huntmaster of the Fells
is a way to gain board presence off an empty board, albeit expensive;
Lightning Helix is insurance against aggressive decks;
Loxodon Smiter is how we make Liliana of the Veil seem like a really, really bad Magic card, and also hurts the occasional Kolaghan's Command;
Selesnya Charm is a fetchable answer to Wurmcoil Engine, Phyrexian Obliterator, large pumped Infect creatuers and the smaller Eldrazi, like both variants of Ulamog. Occasionally, you may give something trample, I guess? I've never done it.
Wear / Tear is good for Bogles, Affinity, Storm, etc. Just a good and versatile card. Consider
Sundering Growth
instead if your meta is light on Spellskite.
Isochron Scepter is to be brought in any time the opponent can't deal with it somehow off the mainboard. It will catch them by surprise, and they will die to Path, Manamorphose, Helix, D/A Command, or Bolt every turn, almost guaranteed. I've been favoring them a little less lately now that Kolaghan's Command is so common, and of course you'd never bring them in against Abrupt Decay decks, but otherwise they do some work. You tend to only bring them in if you don't want Glittering Wish, because you don't want TOO much bad tempo.