Oengus Mac ind-Og
: EHNG-gus MAHC ind-OHG
"Chosen-One the Young Son" or "Son of Youth"
Comparable to the Welsh "Mabon ap Modron
Oengus, sometimes only called "Mac Og," is the Irish god of love, son of the Dagda and Boann. Eternally youthful, he rules at Newgrange, also called Brú na Bóinne for its situation on the Boyne River (named for his mother, or the other way around). He is a god of the otherworld, foster-father of Diarmud and accidental instigater of Edain's problems when he fell in love with Caer, a woman in the form of a swan.
Outside of a few charming episodes like that of the Caer story, and one where he helps his father plan an attack on the Fomorians, there is little said about Oengus. It is believed that he is comperable to Mabon ap Modron, Welsh god of youth, light, and the new-born sun; this is based not only on name (Mabon=Mac Og, as b/p will become c in moving from Welsh to Irish), but on the Winter Solstice occurances at Newgrange.
As such, Oengus, like Mabon, is a fore-runner of other youthful heros like Cuchulainn, Finn mac Cumhail, and Lugh Lamhada, just as Mabon is a fore-runner of Pryderi, Peredur/Perceval, Lancelot and Gawain. As Mabon and Oengus are the same, one can look at the remains of their stories, compare them with recurring themes in the stories of the heros listed above, and be able to come up with a saga of an early god of youth, usually identified with the Gaulish Maponos, who later developed into the Grail knight, while his father/uncle became the Fisher King.