Ghost

Ghosts are a recurring race in the Legend of Zelda series. Ghosts are the physical representation of the spirit of a dead person. Many different types of ghosts are encountered throughout the series. The word "ghost" is used as a collective term, meaning all different types. Some are common enemies, some are more benevolent, some show sentience, and others seem to be bent on destroying Link out of pure hatred and malice.

The dead among the living
Many reasons are given in real-world folk lore about why ghosts return to the living, but in Hyrule (and other lands throughout the series), the friendly ghosts return because they have something they must do that they were prevented from doing because of their death, such as fixing a mistake or teaching someone something utmost important. In the more evil variants, it is hard to say as they rarely speak or show much sentience. As many ghosts appear in graveyards, it can be guessed that at least the lesser ones are tied to their bodies.

There are many different designs of ghosts and many types are not consistent with the designs in different games. The exception would be the Ghini, who look similar to their different incarnations throughout the series. The Poes, on the other hand, are very different from game to game.

Ghosts in combat
It is often shown that ghosts are easily defeated with steel, by means of a sword or an arrow. In folklore edged steel is often a good way to shield yourself from the supernatural, both against ghosts, goblins and the Fae. This could explain why Link is able to defeat ghosts even with non-holy weapons such as standard arrows or the Biggoron's Sword. Ghosts are able to glide through physical objects such as tombstones and walls. If ghosts have a physical body can be debated, and the Zelda games are not consistent about it. Ghosts can cause physical damage to Link, and throw him to the ground and they themselves take damage from physical attacks, but can as mentioned walk through walls and other objects. It is not clear how a ghost's body works in the series.

In Twilight Princess, Link can only see ghosts if he is in wolf form. This means that he can only defeat them if he attacks them with his bare teeth and claws. This is possibly due to the fact that Link has become a "sacred beast" and not just an everyday wolf.

Common ghost enemies

 * Boo Buddy - ghost enemies from Link's Awakening. Originally from the Mario series.
 * Big Poe - bigger version of Poes.
 * Ghoul Rat - ghostly versions of rats.
 * Ghini - common one-eyed ghost enemies.
 * Giant Ghini - bigger version of Ghinis.
 * Hue - Dark World version of Poes.
 * Imp Poe - variation of the normal Poe.
 * Poe - common ghost enemies (can sometimes be friendly).
 * Pols Voice - though they don't look it, The Legend of Zelda instruction manual states that they are ghosts.
 * Reapling - Grim Reaper-like enemies.
 * Rupee Wraith - Evil entities that haunt the living.
 * Them - stated to be ghosts, but are more likely aliens.

Malevolent ghosts

 * Death Sword - Twilight Princess
 * Diabolical Cubus Sisters - Phantom Hourglass
 * Ghost Ringleader - Freshly-Picked Tingle's Rosy Rupeeland
 * Giant Ghini - Oracle of Ages
 * Jalhalla - The Wind Waker, Four Swords Adventures
 * Phantom Ganon - Ocarina of Time
 * Poe Sisters - Ocarina of Time, Majora's Mask
 * Amy
 * Beth
 * Joelle
 * Meg
 * Poes - Oracle of Seasons
 * Shadow Hag - Oracle of Ages

Friendly ghosts

 * Brant - Phantom Hourglass
 * Bremeur - Phantom Hourglass
 * Clock Poe - Oracle of Ages
 * Composer Brothers - Ocarina of Time, Majora's Mask
 * Flat
 * Sharp
 * Dampé - Ocarina of Time
 * Darmani - Majora's Mask
 * Desert Piratian - Oracle of Seasons
 * Doylan - Phantom Hourglass
 * Fado - The Wind Waker
 * Gina - The Minish Cap
 * Hero's Shade - Twilight Princess
 * Kamaro - Majora's Mask
 * Kayo - Phantom Hourglass
 * King Gustaf - The Minish Cap
 * King Mutoh - Phantom Hourglass
 * Laruto - The Wind Waker
 * Lucky Lee - Phantom Hourglass
 * Map-Seller - Freshly-Picked Tingle's Rosy Rupeeland
 * Max - Phantom Hourglass
 * Nostalgic Ghost - Link's Awakening
 * Phantom Guide - Ocarina of Time
 * Phoeni - Skyward Sword
 * Princess Zelda - Spirit Tracks
 * Queen Rutela - Twilight Princess
 * Spookter & Spekter - The Minish Cap
 * Swiftblade the First - The Minish Cap