User blog comment:Xilinoc/Ch. 638 - Boiling Malice and Total Comedy/@comment-25897574-20150807093718/@comment-11051098-20150809032708

It's certainly been an unusual fight, with the opponent being a huge arm.

It could be as simple as Yhwach somehow captured the Left Arm and brainwashed it into believing it is a Quincy and a Sternritter, before he bestowed it with The Compulsory, but I think that option is too boring, too easy to pull off.

I hope for the option that Pernida is some kind of parasitic being or something that controls the Left Arm and has yet to be shown.