Royal Guard’s Gear
It seems everyone at Riverside Stable is especially curious about Hyrule Castle. Talk to Parcy who is standing inside the Riverside Stable building. She will ask you if you know anything about weapons used by Hyrule Castle’s royal guard back in the day. Basically, you need to go into Hyrule Castle and find information on the royal guard’s weapons by finding their actual weapons strewn about the castle. That sounds like fun, right?
The Royal Guard’s weapon series consists of a Claymore, a Spear, a Sword, a Shield, and a Bow. Note that the Royal weapons like Royal Bow or Royal Claymore won’t work. The Royal Guard’s weapons are a deep purple/black color scheme, so you’ll know them when you see them.
The easiest way to complete this sidequest is to go to the Lockup inside Hyrule Castle. If you have already unlocked the Saas Ko’sah Shrine, then you can fast travel there for easy access to the Docks. If you have not yet, then all you need to do is go to the area southwest of Hyrule Castle.
Side note: Learn about how to unlock Saas Ko’sah Shrine for an easy fast travel point into Hyrule Castle.
You will see a raft. Using a Korok Leaf, ride it around the west side of Hyrule Castle. There, you will see an entrance. This leads to the Docks. Instead of going in, however, you will want to climb up the cliffs to the right of the entrance. You will see a Guardian, and behind that, a tunnel entrance marked by Luminous Stone Ores.
Enter the tunnel and use Cryonis to raise up the gate. You will now have entered the Lockup, Hyrule Castle’s jail. Kill the Ganon eyeball to your left to unlock the cell nearest to you.
Now you can pick up the Royal Guard’s Claymore laying inside. This is the easiest, quickest weapon to get to complete the sidequest so you can return to Parcy now.
Once you have shown Parcy any piece of the Royal Guard’s weapon series, she will gift you a gold Rupee worth 300 Rupees.
For those seeking to complete the set and/or fill out the Hyrule Compedium, you can find the other weapons in the Royal Guard’s series as follows.
Past the library in the armory room, you can see the Royal Guard’s Bow and Royal Guard’s Shield hung up on the wall.
Another Royal Guard’s Bow is present in Princess Zelda’s Bedroom.
The Guard’s Chamber is home to a Moblin that is holding another Royal Guard’s Claymore. Defeat it or disarm it to take the weapon.
There is a tall shaft underneath Hyrule Castle leading to a mine cart track. A Moblin there wields the Royal Guard’s Spear.