Empathy Link

An Empathy Link is a telepathic contact from one person to a Satyr from a great distance apart.

Description
This communication can occur when both persons involved are awake or if one of them is sleeping. When one of them is sleeping, the other can show a virtual image of where he is through the person's dream. Both users also have the ability to sense where the other is and somewhat read their emotions. If one person dies, the other will most likely die as well. An empathy link can only be abolished if the two users are face to face and only if wanted.

The only example of an empathy link in the series is the one shared by Percy Jackson and the satyr Grover Underwood.

The Sea of Monsters
Grover opens an empathy link to his best friend Percy Jackson after being taken prisoner by Polyphemus. Percy and Annabeth Chase go to Grover's rescue. While Percy sleeps, Grover is able to transmit images of his location to Percy's dreams.

At the end of the book, Grover offers to have the link removed, explaining that it could kill Percy if Grover died, but Percy convinces him to leave it.

The Titan's Curse
Aphrodite confronts Percy about his true intentions of going on a quest to rescue Artemis, knowing it was really to save Annabeth. Percy lies to the other questers about the meeting, but Grover is able to read his emotions well enough to figure it out.

Luke Castellan tries to convince Thalia Grace to join Kronos' side, trying to get her to summon and destroy an Ophiotaurus Percy had named "Bessie." Once Percy starts thinking about Bessie, he begins to draw the monster towards him, and Grover has to mentally contact Percy and tell him to stop.

The Last Olympian
Grover's disappearance distraughts all his friends, but Percy senses his friend in Central Park and uses the empathy link to communicate with Grover and snap him out of his deep sleep caused by Morpheus.

The Son of Neptune
When Percy arrives at Camp Jupiter, Don the faun sniffs Percy and tells him he has an empathy link with a faun. Fauns being the Roman version of satyrs, Don smells Percy's link with Grover.