With level 9 talent
ish*
I think I'll crack the 10k with the 3rd slash, once I get it leveled to 10. Just need one more Mudra of the Malefic General next monday.
Oh and I like to run him with Kazuha and after a swirl, I see anything between 14k and 16k slashes. Although it's not just the swirl, it's also Freedome Sworn.