Iron Knuckle

Iron Knuckles are heavily-armored soldiers.

Zelda II: The Adventure of Link
They appear in orange, red, and blue throughout the palaces, and were presumably placed there by the King of Hyrule. They move relatively fast, and are capable of slashing their swords at chest height and knee height. They also have shields to block Link's own attacks. The blue ones are additionally capable of throwing knives or Sword Beams, depending on the version of the game. Down Thrusting can be done to avoid an attack being blocked by the shield, though a blue one may be too fast for this to be effective in some situations. The boss of the Island Palace, Rebonack, is an Iron Knuckle that rides a metallic horse that can run on and off the screen. He is later found twice in the Three-Eye Rock Palace.

The Legend of Zelda: Ocarina of Time
They are found in the Spirit Temple as mid-bosses and Ganon's Castle as enemies, and appear with various colors. However, the colors do not signify any strength difference. They are much wider and much slower than in Zelda II: Adventure of Link, and additionally wield huge axes. However, a pre-release screenshot showed a golden Iron Knuckle with armor resembling their previous design. To attack, Iron Knuckles will swing their axes at Link for massive damage, even capable of destroying certain stone structures. Most items will not damage them. Once they have taken enough damage, their outer armor will fall off, and they will become faster, but more vulnerable.

One unique Iron Knuckle with only one phase of battle is revealed to be a brainwashed Nabooru. In fact, in the original version, all Iron Knuckles have Nabooru-like Gerudo faces under their helmets, potentially for testing purposes, as they use a prototypical design. They can be seen by positioning the camera just right through the front of the helmet. In the 3DS version, all the faces were removed, except for the one that houses Nabooru in-story. However, the top of a Gerudo torso can be seen, and in fact is visible in the second phase of battle in this version. All Iron Knuckles have very deep vocal grunts, despite all of them being ostensibly female in this game.

In Master Quest, one appears in the Fire Temple, and some are also in the Gerudo Training Ground.

The Legend of Zelda: Majora's Mask
Iron Knuckles appear three times. Twice as minibosses underneath the graveyard in separate graves, and another time as a lifeless, sword-wielding suit of armor in the Curiosity Shop. On the other side of its helmet is a hole in the wall Kafei uses to spy on what happens in the shop. The fightable ones look and act exactly the same as in Ocarina of Time, and keep the same Gerudo head in the original.

Zelda: The Wand of Gamelon
An Iron Knuckle is a boss, having kidnapped all of Sakado's residents and taken them to Tykogi Tower, despite Mayor Cravendish telling him that that is "illegal." Once he is defeated with the Power Glove, his Armos minions watch him break apart, revealing a beating cartoonish heart.