Suits of armour come in all shapes and sizes and are bewitched to move and talk. There are many suits of armour at Hogwarts School of Witchcraft and Wizardry. During the Second Wizarding War, Professor McGonagall animated these armour to defend Hogwarts against oncoming Death Eaters. The shields of the suits of armour in the front row are immuned to magic spells. During the war, the Death Eaters tried to destroy these armour by simply using the Killing Curse, but their shields deflected all oncoming spells, therefore the Death Eaters cannot defeat them easily.
In 1991 and 1992 some of them were bewitched by an unknown to be evil and attack Harry Potter[1][2], and in the latter they missed their head, and some green smoke was floating out.[3]
A suit of Armour preparing for battle in the Battle of Hogwarts.
Peeves once hidden inside some during the Christmas during the Triwizard Tournament, when the armours are singing Christmas carols with gaps in between their lyrics, which Peeves filled in with his own very rude inventions; Argus Filch had to extract Peeves on these occasions.
Some of the suits appear to have names such as the Axe Knight, Knight, Dark Knight, and Big Knight. The armour also seem to have a degree of sentience, as a suits head turned to watch Harry go to Umbridge's office, and another suit laughed when Neville tripped on the stairs. Also in the PS1 version of the second video game, Dobby brought some suits to life with a spell, this spell seemed to tickle them to laughing.
The knights that appear in Harry Potter and the Deathly Hallows: Part 2 are not, indeed, suits of armour; they are stone statues and do not come in shapes and sizes such as gargoyles and different animals as in the book. However they have different helmets, and it is possible that 'some of them' are suits as in the book some statues also protected the castle.File:76fbarticle-2005210-0C9FA59400000578-991 634x329.jpg
In Harry Potter and the Deathly Hallows: Part 2, the shields of the suits of armour in the front row have the House crests and Hogwarts crests on them: The far left a Gryffindor crest, the second from the left a Hufflepuff crest, the middle knight the Hogwarts crest, the second from the right a Ravenclaw crest, and the far right a Slytherin Crest.
