By the way, can you recommend any good books on the subject of Irish mythology? You mentioning that great war kind of rings the bell, maybe i want to read more about it.
Irish history and mythology are pretty much inseparable so I'd suggest you read the first history of Ireland written by the monks, the Leabhar Gabhála Éireann (The Book of the Taking of Ireland, also called The Book of Invasions). The basic gist is that Ireland was invaded five times by supernatural races, the last of them being the Tuatha Dé Danann and finally by humans who reached a pact with the Tuatha who retreated underground but who still come out from time to time, which is why people may encounter them.
If you want a quick potted history of the war, this is accurate:
en.wikipedia.org/wiki/Tuatha_D%C3%A9_Danann
For the full mythology you need to read the Four Cycles:
Mythological Cycle: The first Irish mythological cycle details the arrival and disappearance of the first inhabitants of Ireland, a group of godlike or supernatural people called Tuatha Dé Dannan. The disappearance of these people gave rise to the Aos Sí, more contemporary mythical Irish creatures including leprechauns, changelings, and the Banshee.
Ulster Cycle: The second cycle is thought to have taken place in the 1st century, around the time of the birth of Jesus Christ. It details quests and feats of ancient heroes, specifically in the areas of Ulster, in the north, and Leinster, in the east.
Fenian Cycle: The third cycle recounts the journey of the hero Fionn mac Cumhaill and his mighty warriors, known as the Fianna.
Historical Cycle: The final Irish mythological cycle, known as the Cycle of the Kings, is the history and genealogy of ancient Irish royals as told by court poets.
Unfortunately there is really no single source for any of this. No single book covers the whole thing or even a whole cycle but there is a collection of translations of tales from all four cycles by Cross and Slover called "Ancient Irish Tales" which is pretty comprehensive.
Oh and there's also this one, very good.
amazon.co.uk/Early-Irish-Myths-Penguin-Classics/dp/0140443975/ref=sr_1_1?crid=37CAXBNM8LAPA&keywords=early+irish+myths+and+sagas&qid=1706110208&sprefix=early+irish+m%2Caps%2C211&sr=8-1