Gronw Pebr- Celtic FigureMortal"Lord of Penllyn"

While Lleu was away, Gronw took Blodeuwedd to his bed, and together they uncovered the one impossible way to kill her husband. He cast the spear that struck Lleu down, but when Lleu returned restored by Gwydion's magic, that same spear flew back through the stone Gronw hid behind.