User blog comment:Xilinoc/Ch. 556 - The Wolfsbane/@comment-10301320-20131107031818/@comment-14244059-20131108065319

...what? I... what? That's not even close to true.

There are many different styles of writing and while some people just kind of wing it, other people are extremely meticulous in the way that they plan and Kubo seems to do both. I don't think you're giving Kubo nearly enough credit here. While some of the stuff is just improvised (Kubo admits this himself), a lot of the more surprising and serious stuff was likely planned out from the beginning, or at their creation, or he at least had a vague idea that evolved over time and it's clear in the hints he dropped much earlier on.

Making things up on the spot can work great (Toriyama proved that with Dragonball Z), but I don't think that's what Kubo's doing with this Arc.