 Hollows become stronger by eating other souls with the most successful who avoid being slain able to eventually evolve into formidable foes known as which are classified and divided into three succeeding stages.The first stage, the also called , are the result of numerous hollows engaging in a cannibalistic feeding frenzy that merges them into mindless black conglomerate giants, regarded as foot soldiers by Soul Reapers.But a Gillian will sometimes develop a personality from one of the component Hollows, causing it to eventually shrink into the animalistic .