This deck is very, well, weird.
I was running Subira in Brawl on Arena, and realized there was YUGE potential for her to go aggro in EDH. Her ability, and the design of this deck is specifically tuned for 1v1 play only, but it is a beast. This deck is a strage hybrid (I know, people hate hybrids in MtG. Myself included. But it WORKS!) of fast and cheap creatures that mostly do something for us, pinging, and burn. After a handful of runs, I realized just how powerful this build is. It was sort of built to be casual, but I wound up beating some of the best commanders.
Here's the scoop. Subira only costs 3 for a 2/3 with Haste. That alone can swing in for the first few damage of the 30 we need (Chances are we will never win via 21 cmdr dmg). For 1 generic, Subira grants one of our other creatures with power 2 or less unblockable. Some of these same creatures do something for us when they attack. So we can benefit fearlessly.
If the opponent tries to control Subira so you can't use the unblockable ability, that's where gameplan 2 comes in best. Turn and burn. We've got some wheel and looting effects, and ways to keep our hands full of cheap effective burn spells. We can keep our cehap creatures out as chumps if we need blockers, often they'll have static abilities that will compound burn or or have the ability to ping. This gets out of hand super fast in 1v1. In 1v1, even if the opponent is playing mono-blue control, we can more often out race them with spells. For example, if they leave two blue up, and counter a 2/2 creature, we can often just follow up with another, or burn to the face. A lot of the small creatures I chose are that of which NEED to be dealt with. So we have plenty of burn left for removal and to take their life down.
In addition, we have the best ping enabling enchantments. If we get them close enough to zero, we can play Furystroke Giant, or sacrifice all our dudes to Goblin Bombardment or similar (there's a handful of spells that allow us to turn our creatures into direct damage for a win). With cmc so low, we didn't need to fill the deck with too many rocks. Only the best were used. Besides, we are in red, so we don't fear Blood Moon. As a matter of fact, we run one in this build. In the rare chance we wind up playing another mono-red player, we can just loot the Blood Moon away for something else.
Some obvious but cool synergies:
Torbran is stupid good. All of our burn and unblocked damage is compounded thanks to him. If you can get him out, and he isn't removed quickly, it's gonna be a good game. Impact Tremors is huge with him, because we have a ton of cheap creatures in the deck. So easy to do massive damage in one turn. Same goes for Purphoros, plus he's indestructible. With all 3, I doubt anyone can beat you.
Young Pyromancer and Seasoned Pyromancer both get us 1/1 bodies that are red, so in a pinch they are the best chump blockers, or can be made unblockable by Subira and likely can do more than their 1 damage from their power alone.
As a fun sub-theme here, I included self-recurring Phoenixes. Why? Because Phoenixes are cool as heck, come back easily, and protect the sky. Wonderful against Parhelion II or Geist of Saint Traft. I notably omitted Arclight Phoenix, because it's too iffy when in a non-storm deck. Not as easy to bring back as it looks. We don't want to sit on 3 burn spells for a chance to cast them in one turn for example. The phoenixes I chose are much easy to get back from the grave.
We have a copy of Meekstone in here to turn off pretty much any non-weenie opponent's build, and an Ensnaring Bridge here for similar reasons. We can fairly easily keep our hand at 2-3 spells from mid-game on. I didn't focus on a ton of draw, because that's too out of character here, but did include wheels and ways to refill if needed. The idea is to sit safely at 2 or 3, so WE can attack, but they cannot. If it doesn't apply, loot it away.
Gutterspine has always been one of those "I'm on the fence about it" creatures when I used to play Modern Burn (when Guttersnipe was a staple). I realized that this is the best home for him ever. He compounds burn damage, and doesn't need to tap to do so. So if he's our only option for Subira's ability, we can swing in with him too.
Lastly, or MVP spell. Mask of Memory. I didn't want to clog the deck up with tutors, and really it would be a waste of a cheap creature or burn slot to drop in a Gamble which isn't a guarantee. So since there's enough synergy in our main gameplan and focus, I decided to just let Mask of Memory show up when it randomly feels like it. If you're lucky enough to strike gold, this is a low cmc, cheap to attach, draw engine equipment. It's a wonderful fit with Subira's ability, or if she's been tied up too much in a given game you can slap it on a phoenix.
Enjoy!