There are two main variants of the Armaduras: those in all-silver, and those with gold trimming. When walking by the ones that stand still, the player enters a quick time event where they must dodge their attack. Failure to dodge results in heavy damage. Whether the player dodges or not, the Armadura will fall apart.
The ones that move and attack move as fast as the player but take frequent pauses letting the player keep distance so long as they keep moving. Gunfire causes no flinching, but sustaining large amount of damage will cause the Armaduras to kneel over. Taking enough damage to their weak spot will cause a plaga to burst out from the helmet. The silver ones will have type-A plaga while the black ones will have type-B plaga.
After taking the Serpent Ornament a handful come to life around the room and chase you down as Ashely. While trying to escape, three stand at the ready and strike with a single swing of their weapon upon passing.
Two that stay still and attack are in the hall way. Six guard the King's Grail. Three normal silver ones and three stronger black ones, attacking in waves of three. These ones six do not appear in Easy mode as the King's Grail is already placed in the King statue's hands.
When playing as Ashley, because you can not attack them, you can only run. When taking the Serpent Ornament, it is important to start running immediately for the exit. Otherwise, the Armaduras will crowd the doorway making it very difficult to leave.
As Leon, a good way to kill an Armaduras is to aim a shotgun blast at their head. That will usually either stun them so that they need to recover their strength, or instantly reveal the plaga. Instead of taking all of them out one by one, you can expose all of their plagas and then throw a flash grenade, easily killing all in six to twelve shots. Be careful doing this, though - when you fight the black ones, they will spawn type-B plagas with insta-kill capabilities.
Another strategy is to focus on one at a time; blow off their helmets with a shotgun and spray them with the TMP, quickly taking them out. This is a safer way to deal with the black Armaduras.
↑縦斬り (Tate kiri?) translates as "vertical cut". While "Vertical slash" is also possible, "slash" uses its own respective kanji
↑縦斬り (Yoko kiri?) translates as "horizontal cut". While "Horizontal slash" is also possible, "slash" uses its own respective kanji
↑ 1.01.1 (in Japanese) biohazard 4 kaitaishinsho kaitei ban. Enterbrain. p. 123. ISBN 4-7577-2638-4.