The card has flying, vigilance, deathtouch, and lifelink
Yukuhiro waits for the perfect moment, and then executes the unthinkable: he targets Hearfire Hero for Self-Destruct
Provided you run enough lands (38+, easily) and are otherwise fine with impulse draw, then this Sword can probably do a lot of work for you
At the very least, it's certainly trying - in a deck with ways to make Bear creature types stronger, Kudo ensures every creature will benefit, while it can also disrupt strategies that want to hone in on creating a strong board presence with lots of built-in stats
If needed, Le Fou, Instigator can be played to have them Challenge a second time