Batman should be around three times as skilled
as Kazuya, but we all know how skilled Batman
is... Kazuya is still a great fighter. Itīs just
Kazuyaīs superior strenght and durability that
gives him the edge in this fight. One hit from
Kazuya means the death of Batman. But Batman
is skilled enough to dodge and block a lot, so
he should be able to win 3 fights at best.
Kazuya can smash smaller mountains, where as Batman can punch with class 1 strenght at best?
Batman is not fighting one of the usual dummys, Kazuya is very skilled, through not in Batmanīs class. But the moment Batman goes for a pressure point, he is open, and that will mean his downfall by Kazuyaīs hands.
Batman is only as strong as the DC-limit allows a human to be. In Tekken, humen can reach extraordinary amounts of strenght. Ordinary Tekken fighters has usually been seen smashing giant rocks and stuff like that, and Kazuya has trained since he was a little boy. His strenght is superhuman in the DC universe. And he has mad skills, he punched the light out of a candle without hitting the candle. And he generally has a lot of advanced maneuvers.
Kazuya has superhuman durability:
He survived a fall from a mountain when he was 5 years old and managed to climb back up the mountain.
Later he was dropped into a mouth of volacano and he lived through that as well.
Kazuya has superhuman strength:
He can shatter boulders and huge bulletproof robots with his bare fists.
He also has superhuman speed and reflexes, seeing how he killed dozens of armed and trained soldiers that were after him and did it with his bare hands.
Not to menation that he has a devil gene which grants him various powers, icluding flight and tk powers.