User blog comment:Fallenbladr/The Elite Guards Plot & Stuff/@comment-5398287-20141106140629

Honestly, Bazz-B would've been a suitable replacement for Pernida. Much more powerful and versatile in combat.

As stated below, Gremmy was a crazy loose cannon who was literally chained up somewhere in Silbern until Yhwach decided to let him loose so he could take out Kenpachi. He needs loyal, mentally stable (well, as far as a Sternritter's mental stability goes) individuals for an elite guard, not some psychopathic child.