arthur light sword

King Arthur then appeared on
a black steed and carried his brother-in-law
away with him to the castle of the King of Ireland.
In exchange for the promise that he
would never raise his hand again against his
wife, he gave him (l) magic cards that always
win, (2) a fiddle that plays for one who has
never played before, and (3) a cup that is
never empty.
In the meantime, the sister of Arthur was
carried off by the King of the Land beneath
the Waves. Arthur rescued his sister and
killed the king and all his people.
Arthur then searched for a man as strong
as himself. He found and defeated a giant before
the giant's castle in a combat with
stones, and he won from the giant (l) a sword
of light that never misses a blow, (2) a rod
of enchantment, and (3) a healing draught.
He beheaded the giant, but the giant's head
challenged him to a game of cards. When Arthur
discovered that the giant's head was
cheating, he threw the head into the fire.

Irish Arthurian Literature by Connor P. Hartnett