- "Who knew I'd be coming to a kiddie party?"
- — Kazuya Mishima, after Asteroid uses his magic properly in Sleeping Xiaoyu.
- "And now, I bring to you... Kazuya Mishima!"
- — Asteroid before magically bringing Kazuya to Rockoland.
Kazuya Mishima is the son of Heihachi Mishima. He is usually summoned by Asteroid with his magic wand. It is revealed that Kazuya is also Asteroid's best friend during the events of Alisa's Adventures in Rockoland, as he is usually summoning him instead of other Tekken: Blood Vengeance characters. In Alisa's Adventures in Rockoland, his Kyoto Castle entrance laugh from Tekken: Blood Vengeance must be heard or Asteroid's magic will backfire. It is also revealed in Alisa's Adventures in Rockoland that Kazuya's favorite sport is football.
If Asteroid doesn't use his magic properly, Asteroid will say "WHAT?!", then Ganryu will say "That's not it!". If this happens before Ganryu appears, or if Ganryu doesn't appear at all, Asteroid will say "WHAT?!", then either Evil-Man will shout "YOU GOT IT ALL WRONG!" or Rock Buddy will say "Wrong move, Asteroid!".
Kazuya also appears in Barney and the Rocko Squad. He will usually appear after the characters sing "Oh boy, I'm in luck. Here comes that Kazuya Mishima." during Lookin' Around My Neighborhood. He shares his role from Barney and the Rocko Squad with Spyro the Dragon, Kazuya's best friend during Barney and the Rocko Squad.
Kazuya's voice actor when he visits Rockoland is Kyle Herbert. In Barney and the Rocko Squad, his voice actor is also used in the classic Bloopy's Buddies clips, as the voice of Maestro Baton, as well as for Mjolnir in Xianghua in Rockoland.