He is the god of the woodland and water. When Paige Winterbourne, Lucas Cortez and Jaime Vegas try to contact a dead druid, Everett Weber, Esus, his diety, reanimates the body of a dead elderly woman to intervene. In exchange for a pint of Lucas's blood, Esus tells the trio all he knows about the wanted murderer of the Cabal children. He reveals that he only allowed Everettt Weber to be captured because he thought that Lucas and Paige (with their reputations) would be able to prove him innocent. However, shamans made it so Esus could not enter the trial where Everett was sentenced to death, and executed moments after without an appeal.
Esus speaks with an old Scottish accent, and shows a humourous sexual interest in Paige after seeing her choice of red undergarments. He offers to inhabit a male body and asks her, "blond or brunette?" When Paige replies that she likes what she already has, Esus considers Lucas for a moment before replying "I don't see why, but I could do that too." Paige hastily changed the subject.