Based on my first few drafts of Guilds of Ravnica, it seems like Boros is the guild to beat.
The red-white aggressive deck is easy to build, easy to pilot, and very effective. It takes the usual aggro advantage of punishing opponents who play expensive spells or stumble on their mana and adds the Mentor mechanic, which lets early aggressive creatures scale up into the mid game and push out more damage. While by no means unbeatable, the deck is popular and powerful, and so it's worth reviewing how it comes together.
Building Boros Mentor
A good Boros Mentor deck needs a critical mass of one and two drops complemented by a mix of pump spells and removal. I don’t know that there’s a magic number of creatures that actually need the Mentor keyword, but we’re probably looking for at least four. I won’t go over the archetype’s rares because they generally won’t be available to you. Suffice to say cards like Legion Warboss and Aurelia, Exemplar of Justice are great. Play them if you have them.
One-Drops
The absolute best one-drop for the deck is Goblin Banneret. This card is a very high pick and is simply excellent in any deck since it almost always trades up and can snowball counters onto your other creatures. The next best options are Hunted Witness and Haazda Marshal as they create additional tokens to Mentor. Finally, Healer’s Hawk is good as a one mana evasive creature that can usually swing past blockers and easily be Mentored. The lifelink is not particularly valuable to an aggressive deck, but it doesn’t hurt and can matter in the mirror match.
I would not recommend playing Torch Courier. Even though it looks like it should synergize well by putting an extra body into combat via haste, in my experience it was too often just card disadvantage.
Two-Drops
Our best cards in the two mana slot are the two uncommon Mentor creatures, Sunhome Stalwart and Boros Challenger. Both have good stats even without the Mentor keyword, and the Challenger is able to get a third point of power which is important since so many of our creatures will have two power. Legion Guildmage would be next in line, as one of the few ways to close out a game where the opponent stabilizes at low life. When our plan goes well the guildmage is a Grizzly Bear, but if we falter he quickly becomes one of the best cards in the deck.
In terms of the common two drops, they are more or less interchangeable. Some mix of things like Ornery Goblin, Vernadi Shieldmate, and Fire Urchin is fine. Just be careful not to have too many one toughness bodies in the two mana slot. That can become a liability if we don’t get Mentor triggers and the opponent resolves something like Mephitic Vapors or Cosmotronic Wave, or just floods the battlefield with their own soldier tokens.
Three-Drops
As an aggressive deck, we don’t want too many spells that cost more than two mana. Our plan is to overwhelm the opponent quickly, after all.
In a draft however you will usually need to play some number of three drops to flesh out your curve and keep your creature count up. The only three drops I would be happy to play are Roc Charger and Wojek Bodyguard. The bird is particularly amazing at providing evasion to another body while easily picking up Mentor counters itself. On the other hand, Wojek Bodyguard has that valuable third point of power to help keep Mentor triggering, and his three toughness makes it more likely he survives to keep doling out counters.
Our next best option is Skyknight Legionnaire just for being an evasive, aggressive body. I wouldn’t pick it highly, but I’d be fine with playing it. I do not like Blade Instructor, but have played it when I needed more Mentor creatures. She has the desirable third point of power, but a very undesirable one point of toughness, and will quickly eat up your pump spells if you want to keep her around for more than one turn.
Four Drops
The only four mana creature I would actively want is Truefire Captain, as it is a high power mentor body with a relevant triggered ability. I find Parhelion Patrol a lot slower than I'd like, but sometimes it becomes a necessary evil as a way to just punch through damage in the air. Mentor on a two power, four drop isn't great, as by that point our one power creatures are not likely going to have profitable attacks even if we double their power.
Rubblebelt Boar is an interesting option that is sometimes amazing and sometimes a dud. I’ve only played it a few times and have seen both ends of the spectrum. I think I would most be inclined to run it if I had a high mentor count and/or lots of first strike. Personally, I would not play Hammer Dropper as it is just too slow and dies too easily. I believe that card is more sensible as a splash in the Izzet deck with Sonic Assault and Gravitic Punch.
Pump Spells
You will rarely get enough Goblin Bannerets and Wojek Bodyguards to consistently Mentor your two power creatures. Instead you will need to run some number of pump spells to keep the triggers flowing.
In my experience Maniacal Rage is the gold standard for Boros pump. It’s cheap, it grows our Mentor guys so they can generally punch through blockers, and it lets them keep Mentoring other creatures to much larger sizes. As with any pump spell we run the risk of getting two-for-one'd by removal, but this is usually worth the risk especially in the early game. Gird for Battle is an interesting alternative as it spreads the risk against removal spells, but my experience with the card has been underwhelming compared to Maniacal Rage. It seems that adding two power and toughness to a single body just more often swings combat math in your favour than a split of counters on two bodies. Your mileage may vary.
I would not play Candlelight Vigil in a Mentor deck, since it's simply too costly for the one extra power compared to Rage or Gird and the vigilance is often wasted.
In terms of temporary pump spells, I really like a single copy of Maximize Velocity when I can grab it. At its best we play a Mentor creature, buff it, and give it haste getting counters and damage that would otherwise not be possible, setting us up to return the Mentor counter next turn by Jump Start. At its worst we can get something big enough to swing before combat and obtain a Mentor counter that we probably wouldn't have otherwise. We almost always have more lands than we need so Jump Start is a very good ability.
Looking at more traditional combat tricks our options are Sure Strike and Take Heart, which are pretty comparable to each other. I like having about two of these effects in the deck, but am pretty agnostic on the mix. I would note that while it can be tempting to use these instants pre-combat for an extra Mentor trigger, most of the time its better to hold them in reserve to react to blocks.
Removal
Good removal is picked highly in draft, so you generally don’t get a lot of choice here. You’ll play whatever number of Justice Strikes, Lava Coils, and Luminous Bonds you get your hands on. My main tip in terms of removal would be to always try and grab one or two Cosmotronic Wave, since they give you something to hope to draw when the board state turns against you and there's a mountain of blockers in your way. I would avoid playing Righteous Blow as it is much better when killing an attacking creature and we expect to be the one attacking.
That is more or less how you want to draft and build your Boros Mentor deck based on my early impressions. Boros has fast, consistent starts with a decent mid-game and does a great job at punishing slow starts. It is weak to decks that can surgically remove your early Mentor creatures (Dead Weight) or go big in a hurry (Rosemane Centaur), and I would say that the perfectly built Dimir, Izzet, Selesnya, or Golgari deck will usually beat a similarly well built Boros deck. Luckily these "perfect builds" almost never actually manifest themselves in a draft table so Boros remains well positioned overall.
Until next time, enjoy the curves of Banneret, two-drop, one-drop, and Maniacal Rage on Banneret!
