Keep him stunlocked enough, and he really doesn't seem to get the chance. It was a replay obviously, so Yuri had Combo Plus 3, 2, and 1, which is 9 attacks in the basic combo, or something ridiculous like 16 or 17 in his down-combo (which you can only do from behind or else you'll knock him down, and you have to be careful because sometimes he'll turn himself around), then follow that with Shining Fang -> Brutal Fang, use the Arte Extension on Brutal Fang to push Yuri's combo up high enough to activate the Tension skills; as soon as the first Overlimit starts just start spamming Shining Fang right up until the level 3 Overlimit is almost over, then end with a Brutal Fang and try to extend it as long as you can. As soon as you can, just start hitting again and try to do the whole thing over again.
In the meantime, between Repede on full assault (making sure to disable all of his Artes that knockdown), Rita makes with the Bloody Howling to initially get him stunlocked, and then Fireball spamming (10 fireballs, takes a while for them all to hit, by which time she's probably just about done casting the next one, even without any Overlimit shenanigans), and even Raven's Dark Chase - he's my healer, but since I'm not taking any damage I just flick the right stick whenever I can to spam DC - the odds are pretty good that the boss'll stay stunlocked in between Yuri's combos.
Fun fact: The experience that boss normally gives is 12000, meaning that at a max combo of 567, you get just shy of a 12x experience rate if you're using Combo Exp.
In the meantime, between Repede on full assault (making sure to disable all of his Artes that knockdown), Rita makes with the Bloody Howling to initially get him stunlocked, and then Fireball spamming (10 fireballs, takes a while for them all to hit, by which time she's probably just about done casting the next one, even without any Overlimit shenanigans), and even Raven's Dark Chase - he's my healer, but since I'm not taking any damage I just flick the right stick whenever I can to spam DC - the odds are pretty good that the boss'll stay stunlocked in between Yuri's combos.
Fun fact: The experience that boss normally gives is 12000, meaning that at a max combo of 567, you get just shy of a 12x experience rate if you're using Combo Exp.