Mug Ruith (or Mogh Roith, "slave of the wheel") is a figure in Irish mythology, a powerful blind druid of Munster who lived on Valentia Island, County Kerry.
He had a fiery ox-driven chariot with blazing jewels that made night seem as bright as day, a star-speckled black shield with a silver rim, and a stone which could turn into a poisonous eel when thrown in water.
Perhaps due to this array of times and settings, poets attributed the druid with extraordinary longevity (he lived through the reign of nineteen kings according to one story).
The various medieval legends about his adventures in the Holy Land at the dawn of Christendom paint him as an interesting and mysterious character, a defender of paganism and an enemy of Christianity.
[4] He married The Cailleach and together they lived at the site of what is now Labbacallee wedge tomb until, in a fit of jealousy after he fell in love with her sister, the hag threw a boulder at the druid knocking him into the River Funshion where he died.