Kemmo, Ijin's Apprentice is your commander. Play around going tall and fast.
I only have about 1 run left to go out of the 7, but I'm currently right at top 25. How I got so many wins with this garbage, I'll never know.
Pretty much always go Turn 2 Grab Commander > Turn 3 drop Kemmo.
Mulligan aggressively for 3 mana. Don't bank winning a game with only 2 mana.
There are too many cute strategies that try to focus on the commander. There's simply way too much unit hate in this mode that will let you play an early commander and let it live.
Kemmo, Ijin's Apprentice is a fantastic aggro commander because he has immediate impact on your deck. Expect him to die. You usually want Charge, +2 HP, or Entomb for his hero effect. You need to squeeze out what value you can, but don't ever expect him to live after 1 turn. Get the +7/+7 weapons in your deck and if you draw one soon, then it's pretty much GG.