The project of reconstructing the pre-Christian or at least proto-Christian version of that old traditional Celtic piece of literature is both generous and interesting. Of course it is not scientific but it is a pretty good literary achievement.
This voyage of vengeance, an Irish son wanting to avenge the death of his father at the hands of Viking invaders, is a lot more than vengeance since de facto the son Mael Duinn will not perform his vengeance since in the last lap of his voyage he will encounter a half Irish half Viking witch who will pretend she has already killed the man. A vengeance by proxy or something of that sort.
The voyage itself is a lot more fantastic and picaresque or picaresque in the fantastic way than a real epic? The saga - since that's what it is really - takes us from marvelous to bewitched and to diabolical islands, meeting with all kinds of natural or supernatural beings like ghosts, giant insects, dragons, giant horses, and all kinds of human hostile, not so hostile or not hostile at all beings.
We can recognize some bricks coming from various traditions including Greek and even older heritage.
But the most interesting element is that Mael Duinn is constantly oscillating between insanity and pure violence when he is not in his normal state, and that normal state becomes very dubious, doubtful, dubitative, unbelievable or even hypothetical as for its real nature. It is a story in which the characters are confronted to all types of dangerous situations but also to the deepest impulses of theirs; stealing, killing, just enjoying, jealousy. In one word the death instinct is the central focus of the survival instinct of these men, since we only have men on the boat, though some women, at times very dangerous women, are met on the islands. Surviving by killing, it is all about.
That leads to the end of the story that appears as a refuge more than a resolution of the conflict. A refuge in a simple peaceful productive activity like boat-building, or a refuge in a more or less religious activity that puts Mael Duinn in a completely closed bubble of religious protection that goes along with isolation from the world, rejection of women and alcohol, and dedication of one's life to meditation.
Strangely enough the author hint at the geographical situation of Hell in the North and a parallel with Iceland, its geysers, volcanoes, hot waters, etc, in surrounding ice and cold, seems to imply that Hell is Hell because it is a spot of hot activities and explosive eruptions in the midst of a cold universe. Maybe after all the fact that the Vikings must have been coming from Iceland might have been another defining element of that Hell that sends its devils and demons to raid and pillage Erin, Ireland.
The author insists on the Triple Goddess which is a very old and powerful element in that Celtic mythology and religion. The triple goddess is seen as the girl with golden hair that gives love, the mother that gives birth and the hag that gives death. She is fundamental in all Indo-European traditions. It is of course connected with the Moon and its three phases - as Shakespeare counts them - the waxing growing phase, the full mature phase and the waning dying phase. But it has deeper roots in Celtic mythology than the goddess Danu, as much as in Nordic mythology, and it goes back to the triple goddess of the Greeks with Hecate the goddess of the night of death, Diana the goddess of life and hunting in the day time, and Selene the goddess of the moon and the night. And we could go a long way beyond to Sumerian traditions or Zarathustra.
On that point the author is too directly influenced by Robert Graves and the easy interpretation of the triple dimension of women in our human minds by Freudian or Jungian psychoanalysts. It is so universal that Buddhism made it its fundamental and central concept of "dukkha", the fact that all things material are born, live and die, and nothing is permanent in any way. The recuperation of this oldest myth of humanity by the Christians or rather the three Semitic religions (Judaism, Christianism and Islam) could fill volumes. In my village there is a 12th century stone in a church that represents a wolf, or is it a she-wolf?, we will never know, and it is dedicated to "drimidri", the very triple godly being (here doubled up at the beginning and at the end) that we find deeply invested in Eastern Orthodox Christianism and has to be descended from Demeter also considered as equivalent to Diana in the triple Goddess.
The author could have done a lot more than what she did on that point.
Yet this voyage of Mael Duinn is a founding tale and myth for the Irish Celtic culture, like Charlemagne and Roland in the French tradition, or Barbarossa and Siegfried in the Germanic tradition.
Dr Jacques COULARDEAU