SKAH-hah
The warrior-woman of Alba who trains Cú Chulainn — and, in the wider tradition, Ferdiad — in the arts of war.
Scáthach runs a school of arms on the Isle of Skye (Alba, in the old sources), reachable only by a perilous bridge that turns back all but the most determined warriors. Cú Chulainn crosses it to complete his training, and under her instruction masters his signature weapon, the Gáe Bulg — a barbed spear that cannot be withdrawn without killing whoever it strikes.
She is as much a prophet as a martial instructor: after his training, she foresees the shape of Cú Chulainn's whole career, including his eventual death, in a vision she alone among his teachers is given to see.