Mimir is Odin's uncle and guardian of the well of wisdom. Mimir was beheaded during the Æsir–Vanir War and his living head was brought to Odin, who turned it into fire. In this state Mimir was given the power of prophecy and Odin made him his advisor. Odin sacrificed his right eye to Mimir's well for the wisdom to forestall ragnarök. Later Thor sacrifices both his eyes for insight on how to end the ragnarök cycle.