Hollow (Bleach)
In the manga and anime Bleach, Hollows are evil spirits. During the first part of the manga, they are the principal antagonists. Hollows reside in the hueco mundo, but can cross over to the human world and soul society.
A Hollow is a Plus spirit that has lost it's heart. They are easily identified by the holes in their chests, and their white masks. Any Plus spirit that is not guided to Soul Society by a shinigami will eventually descend into a Hollow. The process normally takes months or years as the inga no kusari, the Chain of Destiny, slowly corrodes. However, the process may be accelerated under certain conditions.
Hollows wear white masks to protect their true identity and to protect them for injuries (although a shinigami with enough power can cut or shoot right through). Different Hollows have different abilities and appearances, the low level Hollows are small and can only attack melee, whereas the bigger and better Hollows have all sorts of killing implements. Hollows can be furry (like mammals) or lizard-like in appearance. Some other ones just look demonic.
Shinigami do not truly kill hollows. A shinigami's zanpakutō purifies the spirit of the sins it committed as a Hollow, and allows it to enter the Soul Society. However, those Hollows who also sinned heavily in life are consigned to Hell.
The Quincy, however, do truly kill Hollows. When a Quincy destroys a Hollow, the spirit is completely annihilated.
The first Hollow that poses a real threat to the main character (Ichigo) is the Grand Fisher, the Hollow that murdered his mother. Grand Fisher uses a tentacle-like limb to create a decoy copy of a person that the attacker cannot hurt (because of their emotional attachment to the subject). Ichigo managed to repel it, but not defeat it outright.
Grand Fisher appeared again after Ichigo had returned from Soul Society and was quickly ran through by Isshin, Ichigo's father.
Hollow army
Just like the shinigami, the hollows have an army. This army consists only of menos, hollows that are combined of many regular hollows. It's unclear yet whether this army was formed by Sōsuke Aizen, or existed before he became its commander. So far (ch. 197), three 'ranks' have been revealed:
- Menos grande (AKA gillian) - The weakest type of menos, they are extremely strong but not agile, and don't have much brain power. They are approximately at the level of a shinigami lieutenant.
- Ajuukasu (could be Ajukas, pluar to Ajuka) - smaller but smarter than the gillians, they are thought to be far superior.
- Vastorōde (probably short for 'vast hollow') - the top fighters of the menos, there are only 20 of these in total. Each of them is stronger than any captain, and therefore Tōshirō Hitsugaya claims that 20 is enough to defeat all of soul society, although the leaders of soul society (including himself) reckon that only 10 'vast hollows' exist.