Gregal

Quote from The Legend of Zelda: The Minish Cap Gregal & the Ghost figurine:

"An old man plagued by an evil spirit. Coming to his aid will bring you benefit in the end, so if you meet him, you must find a way to help him."

Gregal
Gregal is a member of the Wind Tribe who is plagued by an evil spirit. When link fuses kinstones with a stranger in Hyrule Town, who turns out to be a member of the mysterious Wind Tribe, a warp portal to the Wind Tribe's new home in the Cloud Tops opens up near Link's house. Here, Link finds the bedridden old man with a ghost circling around him which only Link seems to be able to see. If Link saves Gregal's life, Gregal will be found later, restored to full health, stretching and exercising in his home. Link will be rewarded with Light Arrows for his help.

However, there is only a limited amount of time to do this. If Link opens the normal path to the Cloud Tops by way of Veil Falls before saving Gregal from the ghost, he will be informed that Gregal has died and Link will not receive the Light Arrows.

Gregal's Ghost
Gregal is being plagued by a ghost that looks very similar to a Rupee Wraith from Four Swords. The ghost is slowly sapping his life force and will eventually kill him if Link doesn't help him in time. The only way to exorcise this vile apparition is to suck it into the Gust Jar, but this is tricky to do because the ghost is constantly moving. Although it's clearly visible to Link, no one from the Wind Tribe seems to be able to see it and they act very surprised when Link talks to them about it later.