Basically, this chapter is focused on Kawamatsu. Apparently, he had been busy before he was caught and he has the solution to the alliance's weapon shortage problem.
Hiyori certainly mentions something very interesting in this chapter, a sword that left a scar on Kaido. Luffy is the one who aims to defeat Kaido, but he's no swordsman. However, this chapter implies that this sword will have an important role later on if not just being a substitute for Shusui. Speaking of swords, what happened to the one Luffy borrowed from Tama's master.
This chapter also reveals something interesting about Gyukimaru. So what exactly is he? A real magical creature or another Devil Fruit user?