The earth link allows the Warden of Althain to encompass and understand a multiplicity of events on Athera and its linked worlds, from the movement of armies to the movement of a field mouse, without being overwhelmed. Sethvir can see the broader view of events, as well as the multiplicity of possible outcomes in the future. The further into the future, the more indeterminate they become. He is only limited by what he can retain in his memory. The gift of the farsight granted to the s'Ahelas family is similar, but lacks the same breadth of awareness.
The earth link was originally forged by centaurs in First Age 1, when the Paravians arrived on Athera. Sethvir inherited the earth link (and the role as Warden of Althain) from the Paravians and spent many years in training, finally claiming the office in Third Age 5100. When Sethvir uses the earth link, his physical reflexes are slowed.
- The earth link does not work when Sethvir has crossed into a grimward. After leaving the grimward, it takes several seconds to reassimilate the link.
- In Ships of Merior, Arithon contacts Sethvir by writing a message in blood upon a slate, drying it over an open flame, and tossing it into the ocean. This multiplicity of elements causes the event to stand out over the earth link. This method of contacting Sethvir is used by others, such as Dakar later in the story.