User blog comment:Lia Schiffer/400: Deicide 2/@comment-1393830-20100416060358

@WhiteArmor: You want a reason for zero squad to show, I will give you one that makes perfect sense that you cannot deny.

Aizen's goal is to make the kings key and kill the Soul King. The Zero squad serves to protect the king. Aizen is a threat to the king and it is the duty of the zero squad to stop him.