User blog comment:Xilinoc/Ch. 643 - BABY,HOLD YOUR HAND 6 (Waiting for Love)/@comment-25897574-20150918000228/@comment-11051098-20150918182754

Seeing as Yhwach absorbed the Soul King and Pernida is its left arm, it could theoretically work like that, with Yhwach gaining more from Pernida than just the soul piece. It's just a theory though.