Rounding out our modern re-tellings of the Morrigan's interactions with Cu Chulainn we have what may be called the final chapter of the Ulster Cycle, the Death of Cu Chulainn. I will say this, there is some disagreement about some of the details here, specifically in some places who was doing what, and there are also more than one version of this story. I am giving a re-telling which I feel is true to the spirit of the originals, but of course I encourage everyone to read the originals themselves
The Death of Cu Chulainn
The cattle raid of Cuiligne was done and over and Cu Chulainn had several other adventures since that time, but he had made some dangerous enemies, one of which was Queen Medb who had never forgiven him for ruining her plans to take the Brown Bull, or for killing so many of her champions. And she probably still remembered that time he killed her pet sitting on her shoulder when he flung a sling stone at her, as well. So Medb had gotten together many warriors who also hated Cu Chulainn, and she had gotten the children of Calatin, a warrior Cu Chulainn had killed in the Tain Bo Cuiligne to ally with her against him. The daughters of Calatin were fearsome looking, each having only one eye, and Medb sent them to be trained in witchcraft.
Medb began attacking Ulster again with her army and her new champions, hoping to draw Cu Chulainn out to fight. Initially the people who cared about Cu Chulainn tried to trick him into not joining the fighting in several ways, including sending him to a valley where he would be unable to hear any outside noises, but he still saw the smoke rising from the other army and insisted on fighting.
The night before his final battle the Morrigan broke his chariot, trying to prevent his going because she knew he would not return. When he tried to leave the next morning there were several ill omens, including the weapons falling from the racks and Cu Chulainn's own brooch pin falling and cutting his foot. When he called for his chariot to be readied Laeg replied that for the first time his horse, the Grey of Macha was refusing to be harnessed. Cu Chulainn went out himself and spoke to the horse, who turned his left side to his master three times then cried tears of blood at his feet.
All the women wept to see him going, and after he left he saw a woman [the Morrigan or Badb] washing bloody clothes in a river. When he called to her and asked whose clothes she was washing she responded that it was his own.
Then he came upon the three one-eyed daughters of Calatin disguised as three crones. They were at a cooking hearth by the side of the road cooking a dog on a rowan spit, and Cu Chulainn had geasa on him not to eat at a wild cooking hearth or to eat his namesake so he tried to hurry past. The three witches called out to him though and asked him to join them, and when he refused they mocked him for turning down their hospitality saying he would have stopped for a grand meal but not for the small bit they had to offer. Since there was also a geis on refusing hospitality Cu Chulainn was literally screwed if he did and screwed if he didn't, so he stopped. One of the women offered him the shoulder of the cooked dog with her left hand and he took it in his left hand and ate, then put the bone beneath his left leg; the arm and leg immediately weakened.
Then he came to the plain of Muirthemne where the warrior Erc has set up an ambush for him, with many warriors waiting. And it had been said that kings would fall by Cu Chulain's spear so they had devised a clever strategy to get him to give them his spear, that is they set up three pairs of men fighting each other and with each stood a satirist. As Cu Chulainn went across the plain fighting the army he came upon the first pair of fighting men and the satirist called to him to stop them, so he did by killing them. Then the satirist asked for his spear, and when Cu Chulainn refused the satirst said he would make a mockery of him for not giving it so Cu Chulainn hurled his spear through the man. Then his enemies, Lugaid and Erc, recovered it and Lugaid asked the sons of Calatin who would be killed by the spear and one replied that a king would be killed by it. So Lugaid threw it and struck Laeg, who was acclaimed as the king of charioteers. Laeg died and Cu Chulainn carried on, removing the spear and driving his own chariot.
Then he came upon the second pair and again was asked to stop them, again killed them and had the satirist demand his spear. Again he refused and the satirist said he would mock him but Cu Chulainn said he had already bought his honor that day, so the satirist promised to mock Ulster if he did not so he threw it through the man and this time Erc recovered it. He asked the sons of Calatin who would be kiiled by the spear and they replied a king so Erc threw it and mortally wounded the Grey of Macha who was called the king of horses. Cu Chulainn pulled the spear out and the Grey of Macha broke free and ran to the Sliab Fuait with half the yoke still attached.
Again he drove across the plain and this time saw the third pair fighting and again stopped them when requested and as before the third satirist asked for his spear. He refused and the satirist said he would mock him but Cu Chulainn said he had already bought his honor that day, so the satirist promised to mock Ulster if he did not and he said he had paid for that already as well. Finally the satirist promised to mock his whole people and Cu Chulainn threw the spear butt first through the man. Lugaid recovered it and asked the sons of Calatin who the spear would kill. They said a king, so as Cu Chulainn drove again through the army Lugaid threw the spear, disemboweling the king of Ireland's heroes. His second horse broke its yoke as well and fled, stranding the chariot with Cu Chulainn in it.
Now he asked his enemies if he could go to the nearby lake for a drink and they agreed as long as he promised to come back, and he said he would or if he could not they would have to come get him. And he held his guts to his chest with his hands and went to get a drink, and wash himself, and prepare for death. On his return to the plain he saw a great pillar stone and he tied himself to it so that he wold die on his feet. When his enemies gathered around him they did not know if he was alive or dead yet, and as they waited the Grey of Macha came back and defended him for as long as he lived.
Finally the Morrigan and her sisters came in the guise of hooded crows and perched on the pillar, or some say on Cu Chulainn's shoulders, and so his enemies knew that the life was gone from him and they closed in to claim their battle trophies, carrying off his head and right hand to Tara, although Lugaid lost his own right hand when Cu Chulainn's sword fell and severed it.
Cu Chulainn's allies were hurrying to the plain and the met the Grey of Macha on the road, covered in blood and gore, and knew that Cu Chulainn had died. And they followed the horse to his body, where the Grey of Macha stood and laid his head against Cu Chulainn's chest in grief.