Iron Knuckle

The Iron Knuckle is one of the toughest sub-bosses Link will have to defeat in Adventure of Link, Ocarina of Time, and Majora's Mask. In Adventure of Link, a boss Iron Knuckle goes by the name Rebonakku. Though quite similar to Darknuts, Iron Knuckles are more powerful but less agile.

The Adventure of Link
Iron Knuckles can be found in many dungeons and caves in The Adventure of Link. They constantly defend with a shield that they move up or down to block Link's attacks and have a high amount of health, making them one of the game's most difficult enemies to defeat. A good strategy Link can employ to defeat these enemies is to jump, and crouch stab at its head as he falls, thus hitting both its top area and its lower area, guaranteeing damage. They come in three variants: orange, red and blue armors. Each form is stronger than the last, and the blue-armored Knight can also shoot sword beams like Link does.

Rebonakku
This Iron Knuckle, known as , rides a ghostly horse, and is the boss of the Island Palace. Link must use the Down Thrust initially to damage him. After enough damage is done, he dismounts his horse, and can then be fought as a normal Iron Knuckle. The trick is for Link to attack while standing and ducking down so that the boss can't block every attack with his shield. The mounted knight is also fought twice as a miniboss in Three Eye Rock Palace (he guards the Cross the first time).

Ocarina of Time and Majora's Mask
In Ocarina of Time, Iron Knuckles are associated with the Gerudo. It swings a mighty axe that deals devastating blows to whatever comes in its way. If Link is hit by this axe, he will lose quite a large amount of life energy.

Iron Knuckles have two "stages": with armor and without armor. While wearing armor, they're slow and impervious to anything save sword swings and bombs. Once enough armor is removed by means of numerous attacks, they become much quicker, but with the added effect of now being weak to arrows, making a long-range attack strategy is effective. However, in the Child half of the temple, Link may enter and leave as he pleases during the battle, as the door is not restrained.

Nabooru is captured and brainwashed by Koume and Kotake, a pair of Gerudo witch sisters. Koume and Kotake then force the brainwashed Nabooru to don armor and protect the entrance to the final chamber in the Spirit Temple as an Iron Knuckle.

When Nabooru is defeated in her Iron Knuckle form, the armor falls away and reveals her, apparently releasing her of her hypnosis. Immediately, the witch sisters appear and threaten to brainwash her again (suggesting that the hypnosis was temporary and had to be maintained). After Link defeats Koume and Kotake, Nabooru becomes the Sage of Spirit and is freed from her hypnosis permanently. The fact that the other two Iron Knuckles in the Spirit Temple dissolve completely when they are defeated suggests that they were animated by magic and not hypnotized people, like Nabooru.

In both Ocarina of Time and Majora's Mask, Iron Knuckles come in three colors: silver, white, and black. Also, in Ocarina of Time is the armor within which Nabooru is encased, which looks slightly different than others. There are only three Iron Knuckles in Majora's Mask and they fight just as they do in Ocarina of Time. Two are beneath the Ikana Graveyard on the first and second day respectively, one guarding the resting place of Flat, and the other guarding a Piece of Heart. The third is on the Moon in the hide and seek game played by Link while in his Hylian form.

There is also Gold Iron Knuckle armor on display in the Curiosity Shop in Majora's Mask.

Trivia
Onox, the main antagonist of Oracle of Seasons, highly resembles the appearance of an Iron Knuckle. The only real difference is that Onox wields a flail while Iron Knuckles tend to use axes.