Do you know what’s great? Doubling things. There’s just nothing as satisfying as making something that was only meant to happen once, happen twice.
This is especially true in MTG, and even more so when it’s your triggers that you’re doubling. One of the new legendary creatures from Kamigawa: Neon Dynasty also loves doubling things too.
Meet your commander

Your commander is none other than Isshin. For those of you who’ve played Sekiro: Shadows Die Twice, don’t worry, we’re not about to say the Sword Saint. No, this is a different person called
Isshin, Two Heavens As One

This three-mana red, white, and black 3/4 has one ability, and it reads, “If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.” So, our aim here is simple then, we’ve just got to keep turning creatures sideways until we’ve won the game.
Of course, we need to make sure we’re getting the maximum value out of our deck, so we’ve put together a few suggestions on what you should include in your new Mardu aggro deck.
Read More: How Good Is Reconfigure In Commander?
The best creatures for Isshin

The most obvious option here is, of course
Aurelia, the Warleader

Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.
. It means that whenever you attack with them, you’ll get two extra combat steps, and you can combine that with
Moraug, Fury of Akoum

Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.
for even more combat steps and even more damage too.
We have two other suggestions here too. The first is
Etali, Primal Storm

Then you’ve got the scholar’s choice,
Sun Titan

Whenever this creature enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.
. Whether you’re bringing back curses, creatures, or just fetch lands, having access to a double titan of the sun is a big deal. It’s value, and that’s really what you’re looking for.
Read More: Commander Challenge – Basilisk Collar
The best support cards for Isshin

One of the best support cards for Isshin has to be
Blade of Selves

Equip {4}
. This is a two-mana equipment card that grants a creature myriad. This means that when it attacks, you get to create one extra copy for each other opponent you control, and have that creature attack them too. Better yet, because of Isshin, you now get even more tokens.
We mentioned the curses already too. That’s because Isshin doesn’t just trigger when you attack, but when any creature attack. This means that if you play
Curse of Opulence

Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this token: Add one mana of any color.")
, you’ll get even more Treasure tokens whenever anyone attacks whoever you cursed. It’s a huge deal, and it can lead to some truly obnoxious turns.
Finally, you’re going to be attacking a lot, so it’s a good idea to have some defensive options too. The best of the bunch, in our opinion, is
Lightmine Field

Read More: Best Starter Commanders – Lyra Dawnbringer