** UPDATED 3/10/2020 - Updated deck and market to adhere to the new black market rules. If you have different or better ideas, let me know in the comments. **
** UPDATED 2/19/2020 - Based on some suggestions from the comments, I have updated the list to something that I like much more and runs much more smoothly. Be careful if you're used to passing the turn quickly or immediately playing a power on your turn! The new Seal of Devotion's warp ability sometimes takes a second to register. The sideboard now has a few budget substitutions when you don't have a playset of mythics. It also has some Market options if you run into situations you don't think the current market can handle.
if you want a low budget deck and here
for a medium budget deck to start from and build up.**
Never and I mean NEVER keep a one power hand, no matter how gas it seems. You will never draw more power and you will lose.
Always grab the 4th land with Ixtun Merchant if you have no more in hand.
Otherwise, always grab Kyojun.
If you're against an aggro deck, always grab Cozin and pump it with Shugo Tactic or a weapon to get a 4/4 flyer.
If you're against mono-spot-removal decks, hold out as long as possible to gain power and then dump your hand all at once to overwhelm their removal.
If you're against Justice board wipe decks, never ever dump your entire hand. They almost always have two board wipes in a row once they hit 5 power.
Always ALWAYS play Akko first turn on the play or draw, except for: On the draw against Night decks that have Vara's Favor or the Fire decks that have units that ping upon ETB. Otherwise, go all in with weapons on Akko and pump your Onis with his ability as fast as possible.
Bladekins are ESSENTIAL to winning against Time decks. You have to get these out as fast as possible and all the weapons and pump go on them to increase their size before they get out their 5/6 or the Killer Dinosaurs.
Against Justice flyers, you have to mulligan to hit removal. You simply can't do much on the ground and they won't typically block with them. Also, you have to kill them or go as wide as possible before their stupid 4/8 cranks out more flyers to flood the board.
If you are having a rough go in the middle of an early (first 2 or 3) match, where you have no outs and are just chump blocking drawing power cards, just concede and start a new run. There's no point in wasting time when there's little chance of recovery. It takes literally 10 minutes to get back to the 4th round with this deck.
Against boss decks, you must mulligan to try and hit one drops. This is especially important on the draw. Most boss decks synergize with their match stipulations and will win easily without a board presence.
I don't think it's needed, as this deck is a really easy aggro deck to play and win with, but I can run through a few Gauntlet runs with it on YT if it's needed. The biggest thing to learn is how to play around the various strengths and exploit the weaknesses of the AI decks and play style. That only comes with experience.
Thoughts on Breath of Voprex over Torch? The AI ALWAYS takes the 5 damage so I'm wondering what your findings are with this if you tried swapping it in.