Updated: Jan 15, 2020
In the Dindsenchas there is described a local version of the Lughnasad myth which involves a goddess Carmun/Carmen and her three sons, Dian (Violence) Dother (evil) and Dub (black). They are destroying the fruit of the trees and the crops. Whereas sometimes Balor is seen as a god of blight, these figures certainly fill that roll. They are destructive spirits that seek to destroy the crops. Naturally, Lug shows up to do battle, but he is not alone.
Lug, here called Lug Laebach (the crooked), son of Cather (Fair Warrior? fortress?) teams up with two other gods and a goddess, to make it an even match. Be Chuille (woman of the Hazel Tree), Crichenbel (Strong Confines, Strong Boundaries), and Aoi Mac Ollamain (poetic Inspiration, son of the highest grade of Fili).
That these figures are the ones selected to do battle shows us the conception of the gods and the different branches of gods as well. These gods and goddesses are again linked back to Dian Cecht and Esarg, and all of them are magical, poetic, often solar-related, and linked to health and crops. In the LGE it says this:
"Dian Cecht had three sons, Cu, Cethen and Cian. Miach was the fourth son though many do not reckon him. His daughter was Etan the Poetess, and Airmed the she-leech was the other daughter: and Coirpre, son of Etan was the poet. Crichinbel and Bruidne and Casmael were the three satirists. Be Chuille and Dianann were the two she-farmers. "
It links the gods to the family of Dian Cecht and sets them as distinct from the family of Cermait and the children of Elatha and especially Delbaeth/Taranis which are largely linked to powers like death, war and terror. That Lug choses these figures as his running mates rather than Delbaeth or other sons of Elatha tells us also this fundamental divide between the natures of the two distinct families of the gods. Lug's fundamental character is related to the nature of the gods of Esarg, not Elatha, and that seems to be related to magic, music, human skills, health, protection, and living things. Be Chuille is also one of the goddesses in CMT when Lug asks what powers the various gods/goddesses have, Be Chuille and Dianann said they could raise up the trees to fight. This relates back to Lleu and Gwydion in Welsh tradition where the trees are roused up to fight.
Lug is thus in the role of helping humanity achieve the harvest and in some ways more in line with the Fir Bolg. A later king of the Fir Bolg was actually named Lugaid. It is thus fitting that his foster mother is the Fir Bolg queen, whose former husband, Eochaid, was described as the greatest and most just of kings, who was killed by the sons of Nemed. The Fir Bolg are fundamentally deities related to the prosperity and fecundity of the earth and Tailtiu is probably akin to Roman Ops or perhaps Ceres.
The entire branch of gods descended from Esarg are associated with human crafts, prosperity, health, crops, music, poetry and beneficial magics but also seem closely linked to solar powers as well, with Etain postulated as a solar goddess. Lug has a fierce aspect from Balor, making him both healer and slayer, but he is nonetheless aligned with the positive traits of this branch which is wealth knowledge, and health securing. He is viewed as a warrior in all sources, but one which breaks the rules of engagement by being able to strike imperceptibly from great distance, so that he is sometimes called "the caster" or "the shooter". He decides the victor in battle with his spear but is also a master sorcerer and poet. He would seem to thus share qualities with gods like Apollo but also with Indra, who is likewise called "caster of the stone". Be Chuille and Dianann, the so-called wiches in CMT or she-farmers in LGE seem to be the tenders of the land and flocks, Crichenbel the establisher of boundaries and the binder, Aoi, just as the name suggests, the poetic inspiration or otherwise the magical force. This is the same force as the Welsh Awen.