Knights of Hyrule
The Knights of Hyrule don't generally play a vital role in the Zelda series but they do appear in many games throughout the franchise. They are sworn to serve the Royal Family of Hyrule and Sages, and they have helped out in the likes of the Imprisoned War where they played a huge role in helping the sages seal the entrance to the Dark World.
The Knights themselves seem to be regular Hylians but what sets them apart is their battle status. They are considered to be Legendary among folklore and seem to be of a higher rank that their counterparts the Hylian Soldiers.
The Adventure of Link
The Hyrule Knights in this game only appear briefly and they seem to have a purple suit of armor and they are also armed with swords. They can be seen in many towns throughout the game, however, they don't have much of a key role to the plot. In fact the only time they interfere with the actual plot is when Link must learn specific sword tecchniques. There are two specific Knights, one located in Mido Town and the other in Darunia Town.
A Link to the Past
The Knights in this game actually serve a key role to the tale told in the prologue. The Knights were a part of the Imprisoning War. They were enforced by the seven sages to fend off the on coming monsters ftom the Dark World to allow the sages time to seal the entrance. They were successful in doing so but the numbers of Knights greatly diminished.
As the Knights greatly diminished it is said that Link from A Link to the Past is the last in the bloodline. It is also stated that only descendents of the Knights were able to draw the Master Sword from the pedestal.
Ocarina of Time
Only the Hylian Soldiers are seen in the actual game. However, there was a brief mentioning of the Knights, when Link goes to buy the Hylian Shield. In the game it states that the shield is just like the one the Knights of Hyrule used to use.
Oracle of Seasons
The Hylian Knights do also make an appearance in the Oracle of Seasons. However, they are disguised as a group of performers, who have the role of saving Din from Holodrum and bringing her to the safety of Hyrule. However, they were unsuccessful as the disguised didn't work and they were killed by Onox.
The Wind Waker
Even though the Knights are not seen within the actual game they are briefly mentioned. It was said that the Knights of Hyrule could not siege Ganon's Tower.
However, a regular item in the game that you can acquire, called the Knights Crest, is a reference to the legendary Hylian Knights themselves. The symbol bears similarities with the crest seen on the Hylian Shield and these crests are mainly acquired by defeating a Darknut.
Four Swords Adventures
In this game the Knights are featured as monsters when Link is tasked with collecting the Royal Jewels. However, later revealed that these monsters are actually are Hylian Knights and they say that this was the work of Ganondorf. The Knights in this game serve the purpose of guarding the Royal Jewels. These jewels are needed for Link to access the Palace of Winds and ultimately save Hyrule.
- Main article: Hylian Soldiers
Only the Hylian Soldiers make an appearance in the actual game but there is a brief reference to the Knights in the game. Ashei states that her father was indeed a Knight and he taught her the ways of war. However, it is relatively unclear whether her father was in fact a Knight of Hyrule.