...Does that mean they are also capable of Shinigami duties? What I mean is if Shinigamis can send souls to Soul Society, does that mean Arrancars can send souls to Hueco Mundo the same way? If true, Aizen really upset the balance of power here. He single-handedly changed the way things work in the afterlife by making Hallows as important as Shinigamis. I wonder if that's what Iceringer meant when he said Aizen was their salvation. Also, now that arrancars exist, what happens to them when they get killed by a shinigami? They're no longer creatures of instinct so I don't think they would be welcome in Soul Society.