This is an animated segment from a BBC show that aired in Northern Ireland.
CuChulainn is sometimes called the "Irish Achilles." He is the demigod hero of a mythic cycle from Pre-Christian Ireland.
Specifically, he is associated with the ancient province of Ulster -- which is the bulk of what is now Northern Ireland. Interestingly, he is claimed as a symbol by both sides of the "Issue" in Northern Ireland. As a purely Celtic hero, he is claimed by those who want to unite with the Republic of Ireland. As the defender of Ulster who repulsed invaders, he is admired by those who want to stay in the United Kingdom.
In any case, CuChulainn is one of those badass warriors from the mythic past and I'm sure you'll all enjoy the shorts.