Darknut

Darknuts are heavily-armored sword-wielding knight enemies.

The Legend of Zelda
Darknuts first appear in Level-3, Manji. They appear in orange and blue, with the blue ones being more powerful. Darknuts can only be damaged away from their shields, and they constantly move forwards with their swords, occasionally turning. They typically try to pursue Link, and very often appear in very large groups. They sometimes appear in water-filled rooms, where Link can use the stepladder to be out of their reach.

The Legend of Zelda: Link's Awakening
Darknuts, known as Soldiers in the Player's Guide, appear as the guards of Kanalet Castle who betrayed Richard. When a sword-wielding Darknut sees link, it will charge at him. Aside from wielding swords, they can be found without them, in which case they will throw spears. In fact, they are just a graphical and statistical replacement of Moblins, Pig Warriors, and Shrouded Stalfos, a fact which can be observed by swimming around the moat; during one screen transition, a Darknut will change into a Pig Warrior, and vice-versa. Inside the castle, one Darknut hides within a Darknut-shaped relief on the wall which can be bombed. This Darknut holds one of Richard's Golden Leaves. In DX, Darknuts, like Moblins, Pig Warriors, and Shrouded Stalfos, are blue. In the Nintendo Switch version, they are black.

The Legend of Zelda: Oracle of Seasons
Darknuts, again known as Soldiers, appear in various dungeons in both red and blue, wielding either swords or throwing spears. They can be found in the Unicorn's Cave, Ancient Ruins, Explorer's Crypt, Sword & Shield Maze, and in and outside Onox's Castle. A stronger golden one can be found along the Western Coast after a specific old man is spoken to.

The Legend of Zelda: Oracle of Ages
In The Legend of Zelda: Oracle of Ages, Soldiers are much more plentiful. Swordless Soldiers appear in the northern half of Talus Peaks outside Symmetry Village, where they are red in the present and blue in the past. Both colors appear in the Crown Dungeon, Ancient Tomb, and Black Tower.

The Legend of Zelda: Four Swords
Darknuts are among the randomly-generated enemies, and are capable of slashing with their swords. They have a "T" on their shields, likely short for their Japanese name, Tartnuc.

The Legend of Zelda: The Wind Waker
A Darknut first appears as the mid-boss of the Tower of the Gods. Later, they appear in a wide variety of colors as regular enemies. Some wear burnable capes, and ones appear with fancier helmets and higher power called Mighty Darknuts. Darknuts are adaptable enemies, able to use a variety of sword techniques and alternate weapons if theirs in knocked away, or fight with their own hands. To defeat a Darknut, Link typically must dodge around behind it while it prepares an attack and slice open the ropes holding its armor on. Once its armor has been removed, it is revealed to resemble a jackal or a doberman pinscher, but with a nose shaped liked Ganondorf's. From here, it can be attacked directly until it is defeated. They drop the Knight's Crest as spoils.

The Legend of Zelda: Four Swords Adventures
Darknuts, known as Chief Soldiers in the Player's Guide, appear as large counterparts to soldiers, and are typically flanked by a battalion of them. They are capable of doing a forward-moving slash attack, and appear to wear bird-like masks. A blue one initially appears as a miniboss at Lake Hylia, and they appear in blue, green, and red as enemies throughout the game. The Knights of Hyrule are shown with the same bodies as Chief Soldiers.

The Player's Guide also once refers to soldiers or guards as "Darknuts."

The Legend of Zelda: The Minish Cap
Parsed Dark Nut, they appear in green with gray trim and white with red trim. They constantly face Link while hiding behind their shields, occasionally slashing at him. The green type is initially encountered in an underground room in Castor Wilds while Link is trying to find a special gold-colored Kinstone fragment. The white type is initially found as the mid-boss of the Fortress of Winds. The green type seems to have more health, while the white type is faster and tends to lunge forward as it thrusts more often. After these, neither color returns until the second floor of Dark Hyrule Castle, where a duo of green and white Dark Nuts is treated as equal to one of the more powerful type called the Red Dark Nut, itself first found in the Palace of Winds and capable of charging its sword into a corkscrew-like thrust. Dark Hyrule Castle also features an even more powerful type than that called the Black Knight.

The Legend of Zelda: Twilight Princess
A Darknut with unusual armor appears as the mid-boss in the Temple of Time, and is capable of many sword techniques. Attacking it successfully and repeatedly chips pieces of its armor away. Once all of its outer armor is gone, it will throw its swords at Link and start attacking him with rapiers. Later, Darknuts with more typical armor appear as enemies deep in the Cave of Ordeals and in Hyrule Castle, where they are fought in pairs. The last set of Darknuts wears a unique set of gilded armor.

Link: The Faces of Evil and Zelda: The Wand of Gamelon
Darknuts appear, and are among the first enemies encountered with a large amount of hit points. Their shields can deflect projectiles such as bombs in some positions.

Hyrule Warriors
Darknuts with the Temple of Time armor from Twilight Princess appear as enemies. They are capable of throwing swords, as well as bumping an enemy with their shield while their eyeholes glow, before a wide slash, which leaves their critical hit bar open. Occasionally, their critical hit bar will seemingly open with no provocation, causing them to be among the simpler enemies to have one. Stalmasters act as stronger counterparts to them, making them the only special troops to have a reskinned version that is not a direct variant, or even from the same time period. Hylian Captains and Goron Captains additionally act similar.

Cadence of Hyrule: Crypt of the NecroDancer featuring The Legend of Zelda
In Cadence of Hyrule: Crypt of the NecroDancer featuring The Legend of Zelda, Darknuts appear as enemies. They resemble their appearance in The Legend of Zelda: The Minish Cap and wield extremely large swords. They notably appear alongside Iron Knuckles in this game, which are depicted as being rounder than the more muscular Darknuts. Normally, they cannot be attacked from the front, but they can perform a Spin Attack that hits surrounding spaces. If this happens, they will become exhausted for several beats, leaving them open to attack. It has a black variant known as a Black Darknut, which somewhat resemble the Black Knights from The Legend of Zelda: The Minish Cap except their palette incorporates red and blue instead of yellow.

Trivia

 * Phantoms from The Legend of Zelda: Phantom Hourglass closely resemble Darknuts, while they and the similar-acting Reaplings all have "Tartnack" in their internal filenames, being the Japanese name for Darknuts. This suggests Phantoms' models were originally intended for Darknuts before becoming a new enemy, or that Darknuts were simply used as a template and placeholder name for the new enemy.