The Dagda, chief of the Tuatha Dé Dannan. Before everything, only two existed, Danu and Donn. The two lovers came together, birthing the first of the Tuatha Dé Dannan. However, the two loved each other so much that they dared not separate their embrace, trapping their children between them. Wishing to free his siblings, the lovers’ son, the Dagda, spoke to his parents to devise a plan. As Danu and Donn could not bear to consciously separate, the Dagda would strike his father allowing enough time for the other gods to escape from their embrace. But when the time came to enact the plan, the Dagda underestimated his own strength and struck his father dead. Danu, overwhelmed with grief, began to sob. Her devastated tears formed a massive wave that washed away the Tuatha Dé Dannan. Donn’s corpse created the land and sky, with Danu’s tears forming the seas. Sprouting from Donn’s corpse arose a mighty tree, with which the god’s used the fruit or bark produced from the tree to fashion the first humans.
Yet, from the sea emerged the demonic Fomorians, who used their powers over the blights of the earth to subjugate both humanity and the Tuatha Dé Dannan. The Dagda was outraged by the horrid actions the Fomorians committed against his kin and humanity. Therefore, the Dagda consulted his wife, the goddess of war and death, the Morrigan. On Samhain the two consummated their love in a river. Afterwards the Morrigan joined the Tuatha Dé Dannan’s rebellion, offering her prophetic abilities and martial tactics. Uniting the Tuatha Dé Dannan and the soldiers of humanity, the Dagda rebelled against the forces of the Fomorians. Later in the war, the united forces could tell that the final battle was near. So in order to stall for time, the Morrigan advised the Dagda to the travel to the Fomorian camp. Once there the Dagda offered them a peace treaty with the Tuatha Dé Dannan, but as expected they refused. Instead the Fomorians forced the Dagda to eat a ridiculous amount of porridge from his magic cauldron, wishing to humiliate him. The Dagda, unashamed and embracing the lunacy, picked up a massive spoon and began to devour the porridge, not leaving a single drop left. With a swollen belly, the Dagda laid down and fell asleep, all the while the Fomorians laughed at him. When awake, he left the camp, encumbered by his full belly. On his way back to the Tuatha Dé Dannan, he was stopped by a beautiful Fomorian woman, announcing herself as the daughter of the Fomorian king Indech. She quickly began to batter him, wishing to make him her personal slave to travel on top of. Encumbered by his full belly, the Dagda couldn’t fight back against her assault. Irritated, the Dagda proceeded to empty his bowels, returning him to his original form. Apparently attracted to this act, Indech’s daughter swiftly fell in love with the Dagda, sleeping with him on the spot. Afterwards the Fomorian promised to aid the Tuatha Dé Dannan in their fight against her kind, the Dagda now gaining both an ally and a lover. In the final battle the Dagda laid waste to his opposition, wielding his magic club that could both bring great destruction yet was also capable of bringing life back to those who were slain. The battle ended as the last blow was struck against the Fomorian leader Balor by the young deity Lugh. After their victory the Dagda gathered Lugh and Ogma to take back his magic harp Uaithne from the retreating Fomorians.
After the war concludes, the Dagda with the rest of the Tuatha Dé Dannan withdraw into the Otherworld through the Sidhe delegated by Manannan. In another myth, the Dagda and the river goddess Boann fall in love. However the goddess was married to the god of the hunt Nuada. When Nuada leaves for an errand, the Dagda sleeps with Boann, impregnating her. To hide this the Dagda uses his powers to make the sun stand still, warping time around Nuada to make the nine months of pregnancy only one day for him. Boann ultimately gives birth to the Dagda’s son Aengus, who once he discovers the truth of his birth, asks the Dagda to help him take over Nuada’s land of Brú na Bóinne. The Dagda has many other children as well, such as Brigit, Aed, Cermait, Bodb Derg, Midir, Ainge, Dian Cécht, and possibly the members of the Morrigna: Badb, Macha, and Nemain.
The Dagda, like the rest of the Celtic gods, was ripped of his divinity by the arrival of Christianity. However, unlike most of the mainland celts, many of the Gaelic myths were preserved in a way in written literature. These writings were euhemeristic in nature, meaning that they adapted these stories to fit into a historical narrative. Not only to fit in with this narrative, but also to adapt the mythology into a Christian framework, the Tuatha Dé Dannan and the rest of the gods were stripped of their divinity. There were differing explanations given to the origins of these figures, some said that they were merely humans with mighty magical powers, others said that they were fallen angels instead, very few though admitted that these figures were in fact worshipped by the ancient celts as gods, such as the Dagda. In this narrative, the Tuatha Dé Dannan were one of a multitude of different “settlers” of ancient Ireland, among which included the Firbolg and the Fomorians. But after the Tuatha Dé Dannan repelled the Fomorians, the final race of settlers, the Milesians, push back the Tuatha Dé Dannan and force them into the Otherworld. Modern scholarship holds the consensus that the Milesians and their victory against the Tuatha Dé Dannan to be a later invention by Christian writers.
Before the influence of Christianity, the Dagda was one of the most important gods in the Gaelic pantheon. The Dagda was most likely considered to be the chief god of the Tuatha Dé Dannan. He was a god of many things, such as fertility, fatherhood, manliness, life, death, the seasons, time and possibly the sky. He represented greatness in its many forms. His title of the Dagda accentuates this, as it translates to “the good god” or “the great god”, playing upon his greatness in all things. The Dagda has many more names he has gone by as well, such as Eochaid Ollathair “great father”, Dáire “the fertile/violent one”, Eochu “horseman”, Aed “the fiery one”, Ruad Rofhessa “lord of great knowledge”, Fer Benn “man of the peak”, Eogabal, Cerrce and many more.
Due to their tumultuous history, there is no surviving Gaelic creation myth, as such the one I gave above is my own interpretation of the reconstructions given by Iain MacAnTsaoir and Peter Berresford Ellis. These reconstructions are based on both post-christianization sources as well as Proto-Indo-European archetypes. Every attempt at reconstructing the creation myth given above cannot be relied upon (especially mine), as there simply is no evidence of what the creation myth could’ve been. I do not consider my rendition to be any more accurate than the others, since like them mine is similarly based upon debatable and absent evidence.
In post-christianization literature, the Dagda’s father is named Elatha, strangely making the Dagda the half brother of the god Lugh. Yet despite this, Nuada who is described as the Dagda’s brother in multiple sources, isn’t considered a son of Elatha. This confusion is compounded by the fact that Nuada is described as the brother to the Dagda’s son Dian Cécht. These contradictory genealogies could imply that they were a later addition made by writers to further push the euhemeristic narrative. In some Irish literature, the Dagda was said to have died in the final battle with the Fomorians, succumbing to his wounds after the battle. Nevertheless this is contradicted by other writings that depict the Dagda as surviving the conflict, as seen in him recovering his harp, and in other writings where he is credited with an 80 year reign over the Tuatha Dé Dannan after the war, meaning that his death was likely another addition made by later Christian authors.
The Dagda’s brothers, Nuada and Ogma, form a popular trinity in Gaelic myth, possibly representing a triplicate deity in which they were aspects or manifestations of the Dagda, similar to the Morrigna who form the triplicate of the Morrigan.
The god of death Donn mentioned in the reconstructed creation myth has theological ties to the Dagda, with some researchers believing that they were one and the same as not only was the Dagda associated with death, but he was also occasionally referred to as Dagda Donn. The Romans referred to a “Celtic Dis Pater” a death god who the celts claimed ancestry. Donn is the most common god to be claimed as the “Celtic Dis Pater” but if he was a form of the Dagda then that would mean the Dagda would be connected to the Roman god as well. Another Roman god possibly connected to the Dagda is Jupiter, as in the same text mentioning the “Celtic Dis Pater” the author also mentions a “Celtic Jupiter” which many scholars have likened to the Dagda. The Dagda also holds connections with the Germanic mythos as well, as he has been likened to the god Odin, sharing many of his traits. The Dagda has been likened to other Celtic gods as well, such as the Gaulish Sucellus and the Irish Crom Dubh and Crom Cruach who fought against the Christian Saint Patrick.
In a story revolving around the culture hero Cu Chulainn having one of his young cows being taken by the Morrigan, when the arrogant hero confronts the Morrigan she’s seen herding her livestock with someone described as a “giant red man” though never given a name, it’s generally believed that this man is the Dagda.