Oisin is my favorite story in Irish Mythology. The lines between myth, reality, folklore and Christianity are very blurred and it's hard not to believe in some truth to the stories I share with you. As you know from early episodes he was the son of Finn Mac Cumhaill and his first wife who he found as a deer. The name Oisín means fawn or little deer in Irish. He was one of the brightest and best of the Fianna. He was a skilled warrior, a poet and bard. Oisin also had a strong sense of justice, and he was one of the supporters of Diarmuid against his own father, who he felt Finn was acting unfairly. it is said that he assist monks write down many of the deeds of the Fianna in the interests of historical record. If you believe the story you are about to hear he actually shared the stories with St. Patrick himself!
Irish Mythology - Mythical Cycle - Book of Invasions