An important characteristic of epic heroes is that everything about them is special, right down to the manner/time/reason for their birth. That’s why you’ll get cheesy lines like “he was born on a moonless night, in the middle of a terrible storm”. Heroes in classical tradition are born for a reason, usually in response to some kind of problem. Like how Peter Parker gets bitten by a radioactive spider, becomes Spider-Man, and then coincidentally, a bunch of supervillains appear that only Spider-Man can defeat.
In Ulster’s case, once a month all their menfolk are wracked with horrible pangs, leaving the kingdom open for invasion. They needed a hero.
Enter Cú Chulainn. And his birth is about as special (read: weird and confusing and Extra) as it gets.
Well, the Ulstermen are so taken by the flight and singing of the birds that rather than kill the birds (like they set out to do), they just kinda…follow them. Eventually three of the birds lead them to Bruig na Boinde (Newgrange…which is a couple hours south of where they were…makes you wonder just how long they were running around after these birds). Snow falls over the Ulstermen (another sign of something magical about to happen), and Conchobor sends some people out to find shelter. They happen across a little cottage which, despite it being a little cottage, manages to fit the entire company of Ulstermen. The couple who live in the cottage are more than happy to host the Ulstermen even when, somewhat randomly, the wife goes into labour and, with Deichtine’s assistance, gives birth to a son. At the same time, a mare outside gives birth to twins, which were given to the newborn boy as a gift. It’s all very happy and joyful, but when the Ulstermen wake the next morning, everything but the baby boy and the two foals are gone. The boy was given to Deichtine to raise.
Again: this is all very indicative of a very special individual. These are all signs of the “otherworld”. Very magical.
Unfortunately, the boy only lived a few years after. Deichtine was greatly saddened by the death of her foster-son, and, this is literally what it says in the text, “finally, when she had left off sighing, she felt thirsty and requested a drink from a copper vessel”.
One thing you have to keep in mind with these stories is that a lot of stuff just kind of…happens. For no apparent reason.
But anyway, on to the weirdness.
So, she takes a drink, and as she does, she swallows a tiny worm-like creature. Which makes her pregnant. Yeah. That night, Deichtine is visited by Lug, son of Eithliu (and a god), in a dream. In what almost sounds like a villain’s monologue, he tells her that he was the one who led her to that cottage, which belonged to him, and that she was pregnant with his son. He told her to name him Setanta and that the two colts who were born at Bruig na Boinde with the first boy were to be reared for him.
This is all well and good, until people start talking and gossiping about the mysterious pregnancy of Deichtine. Remember, this is a time when women could be stoned for getting pregnant outside of marriage. Someone even starts the rumour that Conchobor, her own father, is the father. So Conchobor marries Deichtine off to Sualtaim son of Roech to save them both from the shame.
But Deichtine is still pregnant by someone else (deity or otherwise), and rather ashamed by this. Such is her shame that I’m assuming Lug takes pity on her and makes her not-pregnant when she goes to her marriage bed. She then becomes pregnant by Sualtaim, and gives birth to a son, who she names Setanta, who later becomes Cú Chulainn.
That was quite the wild ride. Cú Chulainn was born three times (magic number). He’s going through a transformation from god to mortal. Plus, through Deichtine, he’s of royal blood, making him a quasi-divine princeling. Already we can tell he’s destined for greatness. He’s not about to start farming with that kind of pedigree.