Though most Hollows are simply transformed Human souls, a sub-group of Hollows known as Menos, exist. Menos are conglomerations of hundreds of normal Hollows, resulting in a single composite entity of far greater strength than any normal Hollow.
Menos are created when the void within an ordinary Hollow's heart becomes so substantial Human souls are incapable of sustaining it, at which point it begins devouring fellow Hollows. These cannibal Hollows are attracted to one another, and a mass inter-devouring follows, resulting in a Gillian. Following this transformation, the Gillian can evolve twice more, first into an Adjuchas and finally into a Vasto Lorde, provided certain conditions are met. Menos evolution is not only contingent upon the Menos eating other Hollows, but also upon the Menos' ability to avoid being eaten. If another Hollow succeeds in devouring even a part of their body, evolution becomes impossible for the one who was wounded this way. Menos-class Hollows are considered so dangerous Soul Society sends only highly trained Shinigami teams to handle them. These incursions seem to be rare, however, as Menos rarely leave Hueco Mundo unless attracted by large sources of spiritual power or encouraged to by other forces. There are three categories of Menos: Gillian, Adjuchas, and Vasto Lorde.
Gillian, also called
Menos Grande are the first and weakest of all Menos. In Human terms, they would be considered foot soldiers. There are many of them, and they all look alike. In Soul Society, they are the "Menos" who are generally referred to in textbooks. Gillians are huge, but they are slow and have beast-like intellect. Any captain-level Shinigami can destroy them with ease. Gillians commonly attack in a group, and one is powerful enough to be a challenge for a Lieutenant of the Gotei 13. Gillians typically arrive in the Human World through the use of spatial distortions called Kūmon.
Appearance: Gillians are huge monster Hollows at least 2-6 stories tall, easily dwarfing even the largest standard Hollow. They all have a white mask with an elongated nose. Their bodies are covered from their head to their feet with a black covering reminiscent of a cloak. Around their neck is a row of thin white spikes. They have large, pointed feet wrapped in white bandages. They have large white hands with long, sharp, white nails, but they are commonly hidden within their cloak, rarely revealed even in combat. They have long tongues capable of breaking a fellow Hollow's mask.
Signature Skills: Cero, Kūmon, Negación
Adjuchas are the second classification of Menos. They are smaller than Gillians and far fewer in number. They are much smarter and stronger than Gillians, and are often the ones who lead Gillians into battle. Adjuchas are commonly solitary creatures, rarely joining into groups. They are powerful enough to challenge a captain of the Gotei 13.
Signature Skills: Cero, Garganta, Unique Individual Powers & Abilities
Vasto Lorde are the third classification of Menos and the highest level of evolution. They are extremely small Hollows, roughly the same size as humans, and are extremely rare in number. It is said you can count their entire number within Hueco Mundo with only the fingers on your hand. The combat capabilities of a Vasto Lorde are above those of the captains of the Gotei 13.
Signature Skills: Unknown