Kat's memories of Day 7, 8 and 9 had her facing off against increasingly stronger and more technically proficient versions of the boy she'd faced on Day 6. For some reason Kat didn't understand, every day his hair got longer and spikier and his sword got a little larger even though he wasn't any taller. Kat didn't know what to make of those changes, though Lily had suspicions.
Day 10 brought out a new character, this time it was a large hulking man with no visible weapons. 'He' was a massive 214cm tall (7 feet) with chest hair that looked a little bit like a lotus, and scars everywhere. 'His' head was shaved into a short Mohawk and Kat considered his beard to be quite impressive. It was a little strange that he only wore red underwear and nothing else but Kat didn't ever got long to worry about it. Mai didn't bother starting off weak after the 9th day and started fighting at 'full' strength straight away.
Silly chapter to run through the rest of Kat's training. I guess you could argue it's kind of filler, but I enjoyed writing it and I thought it was a funny way to put Kat through a bunch of fights with various weapons for practice. This gives you a proper sense that Kat HAS experience now. Not a tonne, but enough to use her fans confidently.