Ghost Hunter

The Poe Salesman, also known as the One-eyed Ghost or the Ghost Hunter, is a recurring character in the Legend of Zelda series. He is a mysterious figure draped in purple robes, with a bright red dot where his face would usually be (possibly representing a face or an eye). Interestingly his belt bears an image of the Triforce. The Poe Salesman seems to have a profound insight into Link's situation, due to his purported ability to read peoples' minds. In most instances, the strange demeanor of the Poe Salesman is attributed to the fact that he may be undead.

The Poe Salesman seems to take delight in acts of maliciousness - he clearly remarks that he admires the destruction caused by Ganondorf and considers it to be beautiful. This, coupled with his remarkable knowledge about Link and unknown identity, makes the Poe Salesman an enigmatic and unique character in the Legend of Zelda mythos.

The Legend of Zelda: Ocarina of Time
When Link is an adult, the Poe Salesman runs a Ghost Shop in the devastated Hyrule Castle Town. If Link collects a Poe, the Poe Salesman will purchase it from him for some Rupees. However, should Link collect all of the ten Big Poes found in Hyrule Field, the Poe Salesman will give him an Empty Bottle as a reward. The Poe Salesman also explains how he truly loves what Ganondorf had done to Market, and explains that the devastated, abandoned, ReDead-infested, town is beautiful.

Interestingly, as a child, Link can find a Hylian Knight in the place where the Poe Salesman appears in the future. During the day, he says he is bored and wishes there were more troubles in the world. At night, he mentions that he researches ghosts. Based on this, it is entirely possible that this guard is the person who becomes the Poe Salesman. Also, it is speculated by some that the Boy in the Graveyard becomes the Poe Salesman in adulthood, due to several similiarities.

The Legend of Zelda: Majora's Mask
The Poe Salesman first appears in Ikana Canyon, sitting atop a hill. He tells Link to bring a special mask of Ikana in order to pass. He eventually wins the Garo's Mask from the Gorman Brothers in a horse race, and the Poe Salesman summons a tree, which Link can use to transport himself to the top of the hill with the use of the Hookshot.

After this event, the Poe Salesman is found again in the Spirit House atop Ikana Canyon. Here, he runs a mini-game. To complete the mini-game, Link must defeat the four Poe Sisters within a time limit, which will soothe their souls and let them pass on. After he completes this, he is given a Piece of Heart.

The Poe Salesman is encountered for the last time in the Secret Shrine found at the base of Ikana Canyon's water source. Here, he runs another mini-game; Link must battle four mini-bosses from the dungeons he has completed earlier. When he completes this final task, he is given a Piece of Heart, and the Poe Salesman is allowed to pass on to the spirit world himself.

Theories
There are many theories as to the true identity of the Poe Salesman. It is possible that the Poe Salesman is indeed a ghost himself; the physical manifestation of a character who has died.

Guard
When Link is a child, a Hylian Knight who claims that he is really interested in ghosts can be found inside the small house near the entrance to Hyrule Castle Town. When Link returns as an adult, the small house has become the Poe Shop. It is possible that the soldier was killed during Ganondorf's attack on Hyrule Castle and chose to pursue his interest in spirits as a ghost himself. It could also be that he underwent some sort of transformation with the aid of Ganondorf. It should also be noted that the Poe Salesman has a picture of the Triforce on the wall behind his shop and a picture of it on his belt with the bird-like part of the Hylian crest moved up a little. Out of the people theorized to be the Poe Salesman, the guard (being a Hylian Knight) is the only one that would have a connection to the Triforce.

Boy in the Graveyard
There is also a young boy that can be found playing in the Kakariko Graveyard when Link is a child. The boy buys the Spooky Mask from Link because he is interested in ghosts and the paranormal. Also, he is seen patroling the graves with a stick similar to that of the Poe Salesman's. This child is never seen when Link returns to the village as an adult, and it is possible that he somehow became the Poe Salesman.

The man who "sees the truth"
When Link is an adult, the old man Shikashi can be found around Kakariko Village. He tells him about a man with an eye that could "see the truth". Link eventually retrieves the Lens of Truth, a Sheikah item that allows him to see the truth, from the Bottom of the Well. It is generally accepted that the unnamed character's truth-seeing eye is the Lens of Truth, but it is also possible that he had a real eye that could see the truth. The bright light found in the face of the Poe Salesman could be an eye. It could be possible that the Poe Salesman is the unnamed character, as Shikashi remarks that he long since died.

Garo
In Majora's Mask, the Poe Salesman bears a slight similarity to Garo Robes, spirits of the Garo that once roamed Ikana. His appearance, as well as his frequent re-appearances in the Ikana area and knowledge of the Garo may suggest that he has some connection to the Garo tribe.