Yeah yeah another "serious" pun.
Kazuya's not that bad people, but he is extremely hard to play, in the sense that you have zero flexibility due to his stacking mechanic. In order to play Kazuya, you must have :
4x Kazuya
4x The Hunt is On
And the following are strongly suggested :
4x Mishima Family Bloodline
4x Spinning Demon
4x Unnatural Grace
4x Lightning Uppercut
* * *
I can hear you say "Why Unnatural Grace?" First, it matches all three of his symbols. Second, it triggers the Combo E off of Lightning Uppercut (which is sexy in it's own right) and third it allows for easier playing of Destruction in his Wake because it'll make the attacks easier to pass (oh, by the way, LU is Mid, so it's the first part of the DihW combo).
The rest should be obvious.
Also, Kazuya's main momentum gain will come from Kazuya's Gloves as it's a possible two. I'm playing through Chaos, so I added Hoping for a Real Challenge (again, for the LU) instead of Ascending Zephyr because Zephyr tosses two from my hand and I already need to toss those to power the speed of my attacks and Mishima Zaibatsu Leader. These help immensely.
Standard game should go like this.
T1 : Building
T2 : Attack tossing for momentum (through MZL if they attacked you first or Kazuya's Gloves/Hoping for a Real Challenge)
T3 : Lightning Uppercut brah (will probably do around 13-22 damage, which combined with the second turn of attacks, should be enough for a kill).
You may also build on T2 if you're confident you'll get enough attacks/actions to do the T3 kill. I added Lion Slayer for flavor and because I don't feel comfortable playing without a 2CC. However, it's not really needed. It does help fill out the Kazuya's Gloves part of being a punch though, it's also a good secondary kill condition as just by buffing itself it comes in at 4 mid 10 off the combo. Add in Kazuya for a +1/+2 global buff and you're set to go.
Spinning Demon fetches Kazuya, Mishima Family Bloodline allows for card draw and easy stacking characters. The Hunt is On helps in getting those characters back as well.
Protip : When facing Rashotep, toss LU right after the Unnatural Grace and blow up a foundation ASAP. Rashotep's "lolzuya" stance will be delayed for an attack, allowing you to get a +1/+2 speed buff on the LU.