Celtic/Gaelic Divine Triads:
There are a few different triads within the Celtic world, both among continental Gauls and the more insular Gaels. I’m only going to cover the Gaulic Three-Faced God, otherwise known as Lugos, and then compare him to the Gaelic Three High-Kings and Lugh. His three faces are confusing to parse through, but we find that they are usually identified as Esus, Teutates, and Taranis. Accompanying this god is a threefold sacrifice to the Triple-Deity Lugus recorded as drowning, stabbing, and burning, commonly believed to be in relation to each God of the tripartite. I will mostly be covering my theories concerning this figure.
To begin, I think the name Lugh and Lugos primarily descends from the proto-Indo-European root *leugh “to swear an oath” because both gods are strongly associated with oath-taking. The other possibilites (*leug “black” and *leuǵ “to break”) likely come from his association with the sky and storms.
LUGOS
The later... scholiasts... elaborate on Lucan: they elicit the information that Taranis was propitiated by burning, Teutates by drowning, and Esus by means of suspending his victims from trees and ritually wounding them
~ Commenta Bernesia ~
Lugus was clearly worshiped on his own, seperate from any readily identifiable triad. He was only connected to the three underlying gods by Ludwig Rübekeil, a German philologist, based on the above quote from the Commenta Bernesia. I think this connection is worthwhile for further study.
Teutates, his name could translate to “God of the Tribe” and many Gaulic tribes claimed descent from him. He is generally identified as being a tribal protector god, which relates him to *Xaryomen “God of Kinsmen” a reconstructed proto-Indo-European god who has descendants such as the Indo-Aryan Aryaman, the Gaelic Eremon, and the Germanic Irmun, gods who are the progenitors of their respective tribes and seen a protective companions and kindred allies. Teutates is therefore something of a clannish Household-God and progenitor of clans.
Taranis, his name literally means “thundering, thunderous” which gives him a clear connection to the Indo-European thunder-god, best encapsulated with the Norse Thor and the Gaelic Lugh. Taranis is a bit different though since he is often viewed more as a Sky-God than a Thunder-God and this is due to the wheel that he carries, the Wheel of Time, which gives him authority over seasons. Some relate his club to that of the Dagda. However, Lugh also carries a club that is identified as a thunderbolt, so this could just be more of a relation to a Thunder-God with kingly authority, similar to Lugh. It is the Gaelic Lugh who frees Spring from Winter, so he clearly has authority over the Wheel of Time, no different than Taranis.
This distinction between the thundering Sky-Father and the striking champion was perhaps codified within Gaulic mythology through the integration of this tripartite godhead, along with the lesser known Sucellos who is the Gaulic Striker God generally associated with Thor and Lugh. Personally, I think Sucellos is just a variation of Taranis, but I could be completely wrong here.
Esus, his name comes from the proto-Indo-European word *eis which means “well-being, energy, passion” and he is identified as a God of Nature, often associated with war, healing, trees, bulls, birds, and wetlands. His name could be related to an epithet of the Dagda “Aed” meaning “passion, fire” which could be related to Odin meaning “fury, fire” and both of which might come from the same proto-Indo-European root *heyd which means “to kindle” but this is a tentative connection since there are many other more convincing theories for the root of Odin. If this is true then we are seeing a deep relation between Esus and the “spirit of life” often described as passionate fire, or kindling breath.
However, adding both shade and light to the discussion, we can find that the God of the Wild, Cerunnos, may be associated with Lugus, and this association is shown forth through this curious and obscure idol of Cerunnos, depicting him with three faces (shown below). His tricephalic depiction only gives one angle of relation - but there could be more.

Perhaps Cerunnos was associated with Esus in some way, as they are both associated with animals and wild nature? As a side note, Cerunnos is a God of the Wild Nature and Hunters, and Herne the Hunter (who is Odin in another form) is the God of the Wild Hunt - is it possible that both have ancestry in the same mytho-poetic motif of wild warriors, men like animals? If this is true, then the sacrifices to Esus would make much more sense: they were hung on a tree and flogged, and everyone knows Odin is the Hanging God who had sacrifices made to him through hanging. Esus’s name even means “passion” which is not so far from Odin’s “fury” - all of this would give Esus a high place in Gaulic myth, relating him to kingship and authority - and perhaps the other High Kings of the Celtic pantheons.
Perhaps Esus is related to the Dagda in more ways than just his name? Perhaps he was something of a ruling figure, esoterically hidden by various titles and depictions? We know that the druids liked their secrets.
The Gaulic name Lugus is often related to the Gaelic Lug, therefore connecting the continental understanding of the Three-Faced God with the insular understanding of the Three High Kings. By comparing the Gaelic understanding with the Gaulic understanding, we may begin to parse through the identification of the three aspects of Gaulic Lugus.
For Gaels, there was a conception of the three royal Kings who each governed respective sections of kingly authority, otherwise known as:
The Dagda, the Good God of Druids, representing patriarchal rule, generational authority, divine creation, and many more elements. The Dagda is the All-Father, the Ollathair, and he is related to horses, warfare, magic, kingship, and much more. He commands over the gods, and yet is also a wandering magical wiseman, blind, old, and bearded, hoary and hirsute. He is known as the “passionate red one” and has some sort of connection to Suibhne, the wild poet-king, which makes me think Gaulic Esus is related to him somehow simply through the name.
Nuada Airgetlam, Nuada of the Silver-Arm, denoting kingship lost and regained, his name “Nuada” relates him to fishing, hunting, and finding. This watery connection might make you think of Esus, but there is another Britonic relation to be considered here. Nuada is definitely related to the Britonnic god Nodens, a Healing God of the Sea with one hand. Furthermore, and perhaps most importantly, both are said to be progenitors of ancient Celtic clans, and he often shows up in clan histories as a mythical progenitor, or a euhemerized clan chieftain or king. This relates him to Teutates and Eremon since these are both clannish Household-Gods and progenitors of their respective tribes. He is further related to Teutates this way since sacrifices to Teutates were drowned.
In the Annals of Inisfallen we can find an incomplete entry on Nuada. In an entry on the division of Ireland between the sons of Eremon, it says: "Every family [...] subsequently in Ireland is of the race of Nuada on account of his maintenance by his kinsmen and on account of his patience.” This is what makes me think I am on to something here concerning Eremon, Nuada, Teutates, and the older PIE *Xaryomen.
Lugh Lamfada, Lugh of the Long-Arm, encapsulating the youthful champion, the rising prince, and the avenging hero. He is the monster-slaying Thunder-God of the Gaels, and he is directly related to oaths, justice, young warrior bands, and kingship. He carries a club and many spears, his thunder and lightening bolts, and he rules over the seasons by bringing storms, therefore he has a control over time as well. This is clearly the Gaelic version of Taranis.
I will suggest that the Dagda = Esus, Nuada = Teutates, and Lugh = Taranis, and leave it at that, since there are many theories on this divine tripartite in academia and online. Ultimately though, it should be understood that no Indo-European pantheon is a direct 1:1 representation of another, so these theories of mine are all BUNK! I would suggest taking this down with a large bowl of salt.
I would love some comments expressing new opinions, correcting me on certain things, or expanding on what is here.
Hail the Aos Sidhe! Hail victory, and good-end! o///
Nice one
Speculation is fertile. Nothing interesting ever came out of 'we just don't know'.
Where the historian fear to thread, the poet shall enter with boldness.