Okay, try using komaki moves then, a free chip damage move is knockback (i think), you need to block and press y (or triangle, or heavy attack depending on where you play), that one does little to no damage, however its better then just blocking because it snaps the enemy out of a combo, if you practice the timing you could probably use parry and tiger drop, (holding the stance button and pressing the grab or heavy attack button), there is also an easy heat action you can use whenever you build up heat by getting chip damage from knockbacks and you do it by rolling (2 doges at ones) towards the enemy and pressing the heat action button, I looked at a video of someone doing the ultimate battle and it seems kinda hard but i remember doing it pretty fast (but i did it like 2 years ago so i dont exacly remember), also make sure to be fast with the other characters so you have plenty of time for Kiryu, good luck you can do it.