 Arrancar are introduced into "Bleach" following Ichigo's return from Soul Society, serving as major antagonists until their collective defeat in the Fake Karakura Arc.Most of the arrancar antagonists served Sōsuke Aizen, who used an item called the "hōgyoku" to artificially create more arrancar.While more conscious than their original hollow selves, some arrancars are either sadistic psychopaths or display honor or compassion which resulted in some befriending the heroes.