Shadow Guards appear exclusively in the Sheikah Dungeon
Shadow Guards appear as pitch-black versions of Hylian soldiers with glowing red eyes. The eyes can be seen through their body when facing north. When outside of a light-source, they have a red aura-like outline around their entire body.
Shadow Guards only appear in dark rooms. They patrol a set route around the room, completely ignoring Link as long as he is within a light source. When Link steps out of a light source, it will pursue him at the same speed of a Hylian soldier in alert mode.
Shadow Guards tend to appear alone in a room, though as Link progresses through the dungeon there can be several rooms containing 2 or even 3 to deal with at once. They will stop chasing Link as soon as he enters a light source. Their patrol routes tend to pass by at least one light source, but not directly through it.
How to Defeat: Shadow Guards are normally immune to any attack other than fire arrows, but they become vulnerable to all attacks when within a light source. If Link activates a light source when a shadow guard is within its range, it will immediately try to escape the light, making it difficult to damage them through this method. However, Shadow Guards are defeated in 1 hit regardless of which method is used to defeat them.
Shadow Guards drop several small hearts if defeated within a light source, or a large magic potion if Link successfully snipes one with a fire arrow through the dark.
Upon reaching Link they will perform a simple sword attack that deals 2.5 HP. This attack can be blocked with the shield.