The Wizard King of Munster
Cú Roí mac Dáire was the king of Munster and one of the most powerful supernatural figures in the Ulster Cycle — a warrior and sorcerer who stood outside the Ulster-Connacht conflict that dominated everything else, and whose castle rotated nightly so that no enemy could find its door.
His fortress was Cathair Chon Roí on the summit of Caherconree mountain in County Kerry — a real promontory fort whose remains are still visible. Every night the castle spun, its entrance moving to a position only Cú Roí himself knew. You couldn’t take it by force because you couldn’t find its door.
His most celebrated episode is the Beheading Game. He came to Emain Macha in disguise as a giant churl and challenged the Ulster warriors to a reciprocal beheading contest: he would let them cut off his head if they would let him cut off theirs in return. Laoghaire Buadhach tried and fled. Conall Cernach tried and fled. Cú Chulainn knelt for the return blow without flinching. Cú Roí then revealed himself and confirmed the result: Cú Chulainn was the greatest warrior in Ireland and the Champion’s Portion was his by right.
His death came through his captive wife Bláthnat. She poured milk into the river that flowed from the castle, turning the water white — a signal to Cú Chulainn, watching below, that the moment was right to attack. Cú Chulainn attacked. Cú Roí was killed. The man who had built a castle that couldn’t be found died because the woman inside it told his enemy where the door was.
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