Finn McCool?

As my father, George A. Fair, singer, talker and accordion player, second son of Johnstone Fair, County Tyrone, (County Fair) used to say:

"Finn McCool was an Irish giant, six-foot-four between the eyes."

"He received his education from the druid Finegas, who catches the Salmon of Knowledge and gives it to him to cook. Fionn burns himself while doing so and sucks his thumb, thus acquiring the knowledge... From then on there occurs a series of adventures involving hunting, fighting, sorcery, love, and passion. Fionn has many romances but it is with the goddess Sadb that he begets his famous son, Oisín (Ossian)... Accounts of Fionn's death vary... (one) version contains a typical Celtic motif; the tale concludes that Fionn is not dead but sleeping in a cave, waiting for the call to help Ireland in her hour of need."

Peter Berresford Ellis in his Dictionary of Celtic Mythology (Oxford University Press, 1992)