“I declare rebellion.”
While volume 21 technically contains a complete “new” arc it is an immediate continuation of the last one and the series is filled with layered storylines going all the way back to the beginning. This is not the place to start reading.
Corpse of the Witch (complete: parts 1-6) has the approaching warriors running headlong into the Organizations desperate efforts to survive their assault. They encounter the horrifying Abyssal Feeders for the first time, but much greater worries lie as Dae unleashes his most depraved experiment yet. I found the battle a little drawn out here considering the end makes it clear the fighting will continue on a grander scale in the next arc, but it is still the highly inventive, tense and gruesome action we’ve come to expect in Claymore. The duel of speed is an interesting sub-conflict.
The story is quite focused on the background of three new characters, but such understanding seems likely to be important for the next arc and familiar faces do get a fair amount of screen time. There’s some particularly cool stuff going on with Raki.
There’s a slight shift in focus here that fits fine but I hope doesn’t pull us off to the side too much. That said everything still fits very well into the overarching story and the attack against the Organization is off to an epically violent start.