Clothra

Seems clear that Clothra is actually a byname for Ness/Neasca
----Relating to the Narrative
If Neasca is Isella, and her sisters are Moira and Rosella, then that means that Rosella or Moira could be Clothra?
Might need to rewrite Neasca's origin story
Though, if Medb is Clothra/Neasca's sister, that means she must be much younger than Neasca. Neasca is the mother of Aenfeld, and Medb is of a similar age to Aenfeld when they are betrothed.
The means that Medb's father could still be the same as Neasca's if he had escaped the assassination somehow?
We know that Ruaire Ollathair might actually be Simon Magus.
Is Cahthbad told to kill Ruaire Ollathair, or is he told to kill the King of Airthialla? That distinction could prove very important.
If Ruaire Ollathair is indeed Dagda, that could imply that Simon Magus is somehow Dagda, or has the spirit of Dagda in him the way Medb has the spirit of the Morrigan.
Could be making Tlachtga and Clothru the same person, because of them both having sex with three men at once. Simon Magus' sons, or Clothru's brothers. 
----Character Points
Seems very invested in her brothers having heirs and passing their lineage on
Seems totally unphased by incest
Medb’s sister Clothra held the sovereignty of Connacht at Inis Clothrand before Medb. Thus it was Clothra who used to enjoy the tribute of Connacht (dlegeda Connacht) rather than Medb. Supposedly, on Inis Clothrand there is a well in which Medb used to bath at the entrance of the island (tiprait ar dorus na indsi). The story relates that Clothra has sexual union with each of her three brothers before they fight with and are killed by their father Eochaid Feidlech (Dagda). By all three brothers (Bres, Nár, and Lothar) she bears Lugaid Riab-nDerg. In Cocad Fergusa ocus Conchobair (Dobbs 1923b), Clothra becomes the wife of Fergus.
In Cath Boinde, Clothra is the mother of Cormac, but elsewhere (listed as an alternative story even here) Ness is said to be the mother of Conchobar’s son Cormac. In Compert Conchobuir (Hull 1934; Plummer 1883-5), Ness is the mother of Conchobar as well. In Scela Conchobar maic Nessa (Stokes 1908a), Ness is first the wife of Cathbad, then the wife of Fergus, and then the wife of Conchobar. In Compert Conchobuir, Ness is also said to be a daughter of Eochaid (here Eochaid Salbuide, another name for Dagda). Since both Ness and Clothra are said to be wives to Fergus and Conchobar, both Ness and Clothra are said to be the mother of Cormac, and both Ness and Clothra are said to be the daughters of Eochaid, it seems clear that Clothra is simply a byname for Ness.
Clipped from: https://en.wikipedia.org/wiki/Clothru
Clothru was, according to medieval Irish legend, the daughter of Eochu Feidlech, a High King of Ireland, and the sister of queen Medb of Connacht and Ethniu.[1] When her triplet brothers, the findemna, were fighting with their father Eochu Feidlech for the high kingship, she was concerned that her brothers might die without heirs. She is said to have seduced the three of them, and conceived Lugaid Riab nDerg.[2] The next day, according to legend, her brothers were indeed killed, and when Lugaid was born, he was their heir. His epithet Riab nDerg ("the red-striped") came from two red stripes around his neck and waist, dividing him into three: above the neck he resembled Nár; from the neck to the waist he resembled Bres; and from the waist down he resembled Lothar.[3] Lugaid later also became a High King of Ireland, thus Clothru's incest preserved the line of succession. Incest features further in Clothru's story: she is said to have then slept with Lugaid herself, conceiving Crimthann Nia Náir,[4] who later also became a High King of Ireland. She was thus Crimthann's mother, aunt and grandmother.
The island of Inchcleraun (Irish Inis Cloithrinn) in County Longford takes its name from her.
References
The Metrical Dindsenchas "Cairn Furbaide" Poem 10
Joseph O'Neill (ed. & trans), "Cath Boinde", Ériu 2, 1905, pp. 173–185; Edward Gwynn (ed. & trans.), The Metrical Dindshenchas, Dublin Institute for Advanced Studies, 1906, Vol 4, Druimm Criaich Poem 13: Druimm Criach, pp. 43–57; Vernam Hull, (ed. & trans.), "Aided Meidbe: The Violent Death of Medb" Archived 2013-11-29 at the Wayback Machine, Speculum v.13 issue 1, Jan 1938, pp. 52–61
Whitley Stokes (ed. & trans.), "Cóir Anmann", Irische Texte series 3 vol. 2, 1897, p. 22
R. A. Stewart Macalister (ed. & trans.), Lebor Gabála Érenn: The Book of the Taking of Ireland Part V, Irish Texts Society, 1956, p. 301-303
Appears In
Family
Father
* Eochu Feidlech/Dagda, a High King of Ireland, Dagda
Sisters
* Medb
* Ethniu [Eithniu & Mumain might be the same person]
* Mumain
Brothers: 
* The Findemna
Sons
* Lugaid Riab nDerg [Conceived by sleeping with her three brothers in the same night]
* Crimthann Nia Náir [Conceived with her son Lugaid]