Asking me to explain something so essential to Heroic Spirits without revealing your own secrets? My, that seems a bit unfair.

[He raises an eyebrow, now slipping fully back into the polite banter he tended to do when he was alive. This man - felt a lot like some of the doctors in London's seedy underbelly, doing things with glee that society would never accept.]

...What would you say to an exchange of information? I will tell you of Saint Graphs, and you tell me exactly what 'Arrancar' are.